Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” To advance through the presentation, click the right-arrow key or the space bar. From the resources slide, click on any resource to see a presentation for that resource. From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. You may exit the slide show at any time by pressing the Esc key. How to Use This Presentation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter Presentation Bellringers Transparencies Standardized Test Prep Math Skills Visual Concepts Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atoms and the Periodic Table Chapter 4 Table of Contents Section 1 Atomic Structure Section 2 A Guided Tour of the Periodic Table Section 3 Families of Elements Section 4 Using Moles to Count Atoms

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Atomic Structure Objectives Explain Dalton’s atomic theory, and describe why it was more successful than Democritus’s theory. State the charge, mass, and location, of each part of an atom according to the modern model of the atom. Compare and contrast Bohr’s model with the modern model of the atom. Draw Bohr models of various atoms. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer When scientists wanted to find out what an atom was, they were not able to look directly at what the atom was made of. They had to make inferences from the results of many different experiments. It was like trying to describe a picture, such as the one on the next slide, with only small portions visible. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer 1. Write four sentences describing what you can see of the above picture. 2. What information or parts of the picture would make your descriptions more accurate without revealing the entire picture? Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atomic Theory – Democritus to Dalton Our understanding of atoms required many centuries. The idea of an atom—which means “unable to be divided”—dates back to the Greek philosopher Democritus, who lived in the fourth century BCE. John Dalton developed an atomic theory in Like Democritus, Dalton proposed that atoms could not be divided. Dalton’s was the first atomic theory with a scientific basis. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu John Dalton’s Atomic Theory… 2. All atoms of a given element are exactly alike. 3. Atoms of different elements could join to form compounds. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What Are Atoms? continued An atom is the smallest part of an element that still has the element’s properties. Atoms are the building blocks of molecules. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atom Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What’s in an Atom? Atoms are made of protons, neutrons, and electrons. At the center of each atom is a small, dense nucleus with a positive electric charge. The nucleus is made of protons (a subatomic particle that has a positive charge) and neutrons (a subatomic particle that has no charge). Moving around outside the nucleus is a cloud of electrons: subatomic particles with negative charges. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Parts of the Atom Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What’s in an Atom? continued Unreacted atoms have no overall charge. Although atoms are made of charged particles, they do not have an overall charge because they have an equal number of protons and electrons whose charges exactly cancel. To the right is shown a helium atom, which is made of two protons, two neutrons, and two electrons. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What’s in an Atom? Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Clean sheet of paper…Trifold hotdog, then hamburger, hamburger, hamburger Should have 3 rows of 8 … Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Fill in for the first 18 elements… Symbol and Name Atomic # # protons ________ » Leave this space empty » for now…… » Ready for a boring topic? Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models of the Atom Bohr’s model compares electrons to planets. In 1913, the Danish scientist Niels Bohr suggested that electrons in an atom move in set paths around the nucleus much like the planets orbit the sun in our solar system. In Bohr’s model, electrons can only be in certain energy levels. Bohr’s model of electrons is illustrated on the following slide. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Building Model Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bohr Model of the Atom Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models of the Atom, continued Electrons act more like waves. By 1925, Bohr’s model of the atom no longer explained electron behavior. A new model was proposed, in which electrons behave more like waves on a vibrating string than like particles. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models of the Atom, continued An electron’s exact location cannot be determined. It is impossible to determine both the exact location of an electron in an atom and the electron’s speed and direction. The best scientists can do is calculate the chance of finding an electron in a certain place within an atom. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models of the Atom, continued Electrons exist in energy levels. The number of filled energy levels an atom has depends on the number of electrons. The figure to the right shows how the first four energy levels are filled. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Electron Energy Levels (Bohr-ring……) Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models of the Atom, continued Electrons are found in orbitals within energy levels. An orbital is a region in an atom where there is a high probability of finding electrons. An s orbital is shaped like a sphere: Section 1 Atomic Structure Chapter 4 A p orbital is dumbbell shaped and can be oriented three different ways in space:

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Models of the Atom, continued Every atom has between one and eight valence electrons. Valence electrons are found in the outermost shell of an atom and determine the atom’s chemical properties. Valence electrons are the electrons in an atom that participate in chemical bonding. Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Valence Electrons Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Draw the Bohr Model and list the # of electrons and valence electrons for the first 18 elements… SymbolH Hydrogen Atomic #1 # protons1 # electrons (e-)1 # valence e- 1 Section 1 Atomic Structure Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Atomic Structure Objectives Review Explain Dalton’s atomic theory, and describe why it was more successful than Democritus’s theory. State the charge, mass, and location, of each part of an atom according to the modern model of the atom. Compare and contrast Bohr’s model with the modern model of the atom. Draw Bohr models of various atoms. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 A Guided Tour of the Periodic Table Objectives Relate the organization of the periodic table to the arrangement of electrons within an atom. Explain why some atoms gain or lose electrons to form ions. Determine how many protons, neutrons, and electrons an atom has, given its symbol, atomic number, and mass number. Describe how the abundance of isotopes affects an element’s average atomic mass. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 A Guided Tour of the Periodic Table Bellringer One way to organize a large group of objects is to arrange them into groups of similar objects. This is how scientists organize all of the many elements. Practice the skill of categorizing by arranging the magazines listed below into similar groups. Chapter 4 Calling All Girls Homeopathic Medicine Modern Housekeeping Computer World Sports and Scores Easy Car Repairs Beautiful Homes Calling All Boys The Health Newsletter Auto Racing All About Computing Football Stories The Healthy Man Home Decorating Read Aloud Stories Sporting Times Classic Cars Building a Web Site Child’s Play The Healthy Woman Home Makers Magazine Family Computing Golf for Everyone The Sports Car Story Beautiful Homes Nursery Rhymes Good Nutrition Car Trends How to Use the Internet Tennis Tips

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer 1. What criteria did you use for grouping the magazines? 2. Once you arrange the magazines into groups, could you sort the material further to make it even more organized? Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Organization of the Periodic Table The periodic table groups similar elements together. This organization makes it easier to predict the properties of an element based on where it is in the periodic table. Elements are listed in order of number of protons, because the periodic law states that when elements are arranged this way, similarities in their properties will occur in a regular pattern. Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Organization of the Periodic Table, continued The periodic table helps determine electron arrangement. Horizontal rows in the periodic table are called periods. Just as the number of protons an atom has increases as you move from left to right across a period, so does its number of electrons. Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Organization of the Periodic Table, continued Elements in the same group have similar properties. A group is a vertical column of elements in the periodic table. Atoms of elements in the same group have the same number of valence electrons, so these elements have similar properties. You have to keep your eye on this next topic….. Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Some Atoms Form Ions An ion is an atom that has lost or gained electrons which results in a positive or negative charge. A lithium atom loses one electron to form a 1+ charged ion: Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Some Atoms Form Ions An ion is an atom that has lost or gained electrons which results in a positive or negative charge. Section 2 A Guided Tour of the Periodic Table Chapter 4 A fluorine atom gains one electron to form a 1 charged ion:

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ion Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Do the Structures of Atoms Differ? The mass number, A, of an atom equals the number of protons plus the number of neutrons in the nucleus. The atomic number, Z, of an atom equals the number of protons in the nucleus. This defines the atom type. Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Nucleus Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atomic Number Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mass Number Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Do the Structures of Atoms Differ? continued An isotope is an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons. Student Model H-1, H-2, and H-3 Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Do the Structures of Atoms Differ? Example: Hydrogen has three isotopes, shown below. Section 2 A Guided Tour of the Periodic Table Chapter 4 Some isotopes are more common than others.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Do the Structures of Atoms Differ? continued If you know the atomic number and mass number of an atom, you can calculate the number of neutrons it has. Example: uranium-235 has a mass number of 235. Like all uranium atoms, it has an atomic number of 92. The number of neutrons it has is therefore: Mass number (A): 235 Atomic number (Z):–92 Number of neutrons:143 Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Isotopes Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Do the Structures of Atoms Differ? continued Isotopes: Calculate the number of neutrons there are in the following isotopes. (Use the periodic table to find the atomic numbers.) Section 2 A Guided Tour of the Periodic Table Chapter 4 # protons# neutrons# electrons Carbon-14 Nitrogen-15 Sulfur-35 Calcium-35 Iodine-131

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Do the Structures of Atoms Differ? continued Because the mass of a single atom is so tiny, atomic masses are usually expressed in atomic mass units. An atomic mass unit (amu) is equal to one twelfth of the mass of a carbon-12 atom. The average atomic mass for an element is a weighted average of the masses of all naturally- occurring isotopes of an element. Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Average Atomic Mass (pHet)(pHet) Section 2 A Guided Tour of the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 A Guided Tour of the Periodic Table Objectives Review Relate the organization of the periodic table to the arrangement of electrons within an atom. Explain why some atoms gain or lose electrons to form ions. Determine how many protons, neutrons, and electrons an atom has, given its symbol, atomic number, and mass number. Describe how the abundance of isotopes affects an element’s average atomic mass. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Families of Elements Objectives Locate metals, non-metals, and semiconductors on the periodic table. Locate alkali metal, alkaline earth metals, transition metals, halogens, and noble gases on the periodic table. Relate an element’s chemical properties to the electron arrangement of its atoms. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer Are you familiar with some of the elements on the periodic table? There are probably many more elements that you have never heard of before. You may be surprised to learn that even though you have never heard of a certain element before, by looking at the periodic table, you can guess some of the characteristics of that element. The periodic table organizes elements into groups that have similar characteristics. 1. The elements below are classified as metals. You may be familiar with some of these elements. If you know of a specific use for an element listed below, write it down. Silver, Ag Gold, Au Tin, Sn Copper, Cu Lead, Pb Mercury, Hg Aluminum, Al Platinum, Pt 2. Can you think of any characteristics that the metals have in common? Do any of the metals have similar uses? Section 3 Families of Elements Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer 3. The elements below are classified as nonmetals. You may be familiar with some of these elements. If you know of a specific use for an element listed below, write it down. Helium, He Chlorine, Cl Oxygen, O Iodine, I Neon, Ne Carbon, C 4. Look at the periodic table and notice where each of the elements listed in questions 1 and 3 is located. Where are the metals located? Where are the nonmetals located? Section 3 Families of Elements Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Are Elements Classified? The elements are classified into three groups. Most elements are metals, elements that are shiny and conduct heat and electricity well. Nonmetals, all except hydrogen of which are found on the right side of the periodic table, may be solids, liquids, or gases at room temperature. Between these groupings are semiconductors, elements that can conduct electricity under certain conditions. Section 3 Families of Elements Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How Are Elements Classified? continued The periodic table below shows the distribution of metal, nonmetals, and semiconductors in the periodic table. Section 3 Families of Elements Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Metals The alkali metals, found in Group 1 of the periodic table, are very reactive. Section 3 Families of Elements Chapter 4 The alkaline-earth metals, which include calcium, are found in Group 2 of the periodic table, and are somewhat less reactive than the alkali metals. The transition metals, such as gold, iron, and mercury, occupy Groups 3–12 of the periodic table.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Carbon is found in three different forms and can form many compounds. Nonmetals and their compounds are plentiful on Earth. Nonmetals Section 3 Families of Elements Chapter 4 Halogens, such as chlorine, are located in Group 17 of the periodic table. Noble gases, such as neon, make up Group 18 of the periodic table. They are unreactive.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Semiconductors are intermediate conductors of heat and electricity. Nonmetals, continued Section 3 Families of Elements Chapter 4 Silicon is the most familiar semiconductor. Silicon is an important part of computer chips, as well as other semiconductor devices such as transistors, LED display screens, and solar cells.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Comparing Metals, Nonmetals, and Metalloids Section 3 Families of Elements Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Families of Elements Quick Lab Turn to page 124 in your text for the “Why do some metals cost more?” Quick Lab… Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Families of Elements Objectives Review Locate metals, non-metals, and semiconductors on the periodic table. Locate alkali metal, alkaline earth metals, transition metals, halogens, and noble gases on the periodic table. Relate an element’s chemical properties to the electron arrangement of its atoms. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Objectives Explain the relationship between a mole of a substance and Avogadro’s constant. Find the molar mass of an element by using the periodic table. Solve problems converting the amount of an element in moles to its mass in grams, and vice versa. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Counting Atoms Mini Lab 1. What would the mass of 1000 FIGURES (A, B, C) be? Each student should answer this question for each of the 3 cardboard figures labeled A, B, C. Use the KNOW  GO Unit Analysis Approach. Show ALL of the calculations with UNITS***!!! Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Counting Atoms Mini Lab 2. What would the mass of 5595 FIGURES (A, B, C) be? 3. How many A’s are contained in 1200g pile of A’s? How many B’s are contained in 1200g pile of B’s? How many C’s are contained in 1200g pile of C’s? Each student should answer this question for each of the 3 cardboard figures labeled A, B, C. Use the KNOW  GO Unit Analysis Approach. Show ALL of the calculations with UNITS***!!! Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Bellringer Sometimes when you are dealing with numbers of things, it is convenient to have a special unit that designates a specific number of the objects. Below are examples of special units that are used to count objects. Chapter 4 1. How many objects are in each sample?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Bellringer, continued 2. What if you want to use six sticks of butter, but you only have a large block of butter and a scale? How could you get the equivalent of six sticks of butter without the mess of dividing the large block into sticks? Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Counting Things There are many different counting units: for example, eggs are packaged by the dozen. The mole is useful for counting small particles. A mole (abbreviation: mol) is the number of particles that is the same as the number of atoms of carbon in 12 g of carbon-12. Avogadro’s constant is the number of particles per mole of a substance: × Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Mole Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Avogadro’s Number Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Counting Things, continued Moles and grams are related. The mass in grams of 1 mol of a substance is called its molar mass. (g/mol) For example, 1 mol of carbon-12 atoms has a molar mass of g. The molar mass of an element is its average atomic mass, which is listed in the periodic table. Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Molar Mass (g/mol) Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Calculating with Moles To convert between moles and grams and vice versa, you can use a conversion factor: a ratio that is derived from the equality of two different units. Let’s say that a shopkeeper knows that exactly 10 gumballs have a total mass of 21.4 g. This relationship can be written as either one of two equivalent conversion factors: Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Conversion Factor Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Math Skills Conversion Factors What is the mass of exactly 50 gumballs? 1. List the given and unknown values. Given:mass of 10 gumballs = 21.4 g Unknown:mass of 50 gumballs = ? g Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Math Skills, continued 2. Write down the conversion factor that converts number of gumballs to mass. The conversion factor you choose should have the unit you are solving for (g) in the numerator and the unit you want to cancel (number of gumballs) in the denominator. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3. Multiply the number of gumballs by this conversion factor, and solve. Section 4 Using Moles to Count Atoms Math Skills, continued Chapter g

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Calculating with Moles, continued An element’s molar mass can be used as a conversion factor. The diagram below shows how to set up the conversion factor, depending on whether you want to convert from amount to mass or the other way around. Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Math Skills Converting Amount to Mass Determine the mass in grams of 5.50 mol of iron. 1. List the given and unknown values. Given:amount of iron = 5.50 mol Fe molar mass of iron = g/mol Fe Unknown:mass of iron = ? g Fe Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Math Skills, continued 2. Write down the conversion factor that converts moles to grams. The conversion factor you choose should have what you are trying to find (grams of Fe) in the numerator and what you want to cancel (moles of Fe) in the denominator. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3. Multiply the amount of iron by this conversion factor, and solve. Section 4 Using Moles to Count Atoms Math Skills, continued Chapter g Fe

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Us the periodic table and the molar mass to convert the following moles to grams: 2.50 mol of sulfur S 1.80 mol of calcium, Ca 0.50 mol of carbon, C 3.20 mol of copper, Cu Section 4 Using Moles to Count Atoms Math Skills, continued Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Us the periodic table and the molar mass to convert the following moles to grams: 2.50 mol of sulfur S80 g S 1.80 mol of calcium, Ca72 g Ca 0.50 mol of carbon, C6 g C 3.20 mol of copper, Cu203 g Cu Section 4 Using Moles to Count Atoms Math Skills, continued Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Math Skills Converting Mass to Amount Determine the amount of iron present in 352 g of iron. 1. List the given and unknown values. Given:mass of iron = 352 g Fe molar mass of iron = g/mol Fe Unknown:amount of iron = ? mol Fe Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Math Skills, continued 2. Write down the conversion factor that converts grams to moles. The conversion factor you choose should have what you are trying to find (moles of Fe) in the numerator and what you want to cancel (grams of Fe) in the denominator. Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3. Multiply the mass of iron by this conversion factor, and solve. Section 4 Using Moles to Count Atoms Math Skills, continued Chapter mol Fe

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Us the periodic table and the molar mass to convert the following grams to moles: 4.4 g Si 56.8 g Cu g Pb g Au Section 4 Using Moles to Count Atoms Math Skills, continued Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Us the periodic table and the molar mass to convert the following grams to moles: 4.4 g Si0.16 mol Si 56.8 g Cu0.89 mol Cu g Pb0.48 mol Pb g Au mol Au Section 4 Using Moles to Count Atoms Math Skills, continued Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concept Mapping Section 4 Using Moles to Count Atoms Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Using Moles to Count Atoms Objectives Review Explain the relationship between a mole of a substance and Avogadro’s constant. Find the molar mass of an element by using the periodic table. Solve problems converting the amount of an element in moles to its mass in grams, and vice versa. Rutherford Lab option pHetpHet Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 1. Why do atoms gain or lose electrons? A.to balance the charges between the nucleus and the electron cloud B.to obtain a more stable electron configuration through a full outermost orbital C.to place electrons in higher energy levels than are occupied in the atom D.to reduce the amount of energy required to bring atoms closer together Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 1. Why do atoms gain or lose electrons? A.to balance the charges between the nucleus and the electron cloud B.to obtain a more stable electron configuration through a full outermost orbital C.to place electrons in higher energy levels than are occupied in the atom D.to reduce the amount of energy required to bring atoms closer together Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 2. Why are the Group 8 elements Noble Gases) nonreactive? F.They have no valence electrons. G.They combine to form stable molecules. H.Their outermost energy levels are completely filled. I.They are too rare to react with significant amounts of other elements. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 2. Why are the Group 8 elements Noble Gases) nonreactive? F.They have no valence electrons. G.They combine to form stable molecules. H.Their outermost energy levels are completely filled. I.They are too rare to react with significant amounts of other elements. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 3. Antimony is a shiny, brittle solid that conducts electricity under some conditions but does not conduct in other conditions. How is antimony classified on the modern periodic table? A.metals B.nonmetal C.semiconductor D.transition element Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 3. Antimony is a shiny, brittle solid that conducts electricity under some conditions but does not conduct in other conditions. How is antimony classified on the modern periodic table? A.metals B.nonmetal C.semiconductor D.transition element Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 4. Beryllium is located on the same row of the periodic table as fluorine, while iodine is located in the same column. Identify which element, beryllium or iodine, will form an ion by gaining one electron, as fluorine does, and explain your answer. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 4. Beryllium is located on the same row of the periodic table as fluorine, while iodine is located in the same column. Identify which element, beryllium or iodine, will form an ion by gaining one electron, as fluorine does, and explain your answer. Answer: Iodine will form an ion by gaining one electron, because all of the elements within a column have the same valence electron structure. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Read the passage below. Then answer the question. Particle accelerators are devices that speed up charged particles to speeds close to the speed of light in order to smash them together and observe the results. In many cases, these collisions form a new atomic nucleus. This nucleus attracts electrons and becomes a neutral atom. Atoms formed this way can either be an isotope of a known element or a previously unknown element. 5. Determine how scientists can judge whether the newly formed material is a new element or a new isotope of an existing element. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reading Skills 5. Determine how scientists can judge whether the newly formed material is a new element or a new isotope of an existing element. Answer: They can investigate its chemical and physical properties and compare them to known elements. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Interpreting Graphics Base your answer to question 6 on the illustration below, which shows the ionization of a fluorine atom. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Interpreting Graphics 6. Why is the fluoride ion larger than the fluorine atom? F.The electrons experience a greater electrical repulsion. G.The interaction between the electrons and the protons is stronger. H.The ion has more protons than electrons so it is not as stable as the atom. I.The addition of another electron makes the ion substantially more massive than the atom. Standardized Test Prep Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Interpreting Graphics 6. Why is the fluoride ion larger than the fluorine atom? F.The electrons experience a greater electrical repulsion. G.The interaction between the electrons and the protons is stronger. H.The ion has more protons than electrons so it is not as stable as the atom. I.The addition of another electron makes the ion substantially more massive than the atom. Standardized Test Prep Chapter 4