Bell Ringer # 1 1. Which of the following is the basis for arranging the elements in the modern periodic table? A. Alphabetical order B. Masses of atoms C. Number of protons D. Date of discovery 2. How many elements are listed in the modern periodic table? A. 28 B. 60 C. 72 D. More than 100

Bell Ringer continued 3. What do elements in the same column have in common? A. Similar chemical properties B. Number of protons C. Masses f their atoms D. Size of their atoms

Quiz #1 - Video 1.There are 5 times as many metals on the periodic table as nonmetals. 2.Bromine is a brown liquid at room temperature. 3.Chlorine gas was used as a weapon during WW II. 4.The electrons form rings around the nucleus called shells. 5.Lithium is a hard gray metal.

Quiz #1 – Video - Answers 6. Some Group 1 metals mix with water to cause an explosion. 7.Once the outer shell reaches 8 electrons, it is stable. 8.The noble gases are highly attracted to the alkali metals. 9. Mercury was once used for filling cavities. 10. Many of the metals are dull with no shine. 11. Most of the metals have varying numbers of valence electrons from 4-7.

Bell Ringer #1 1.What are valence electrons? 2.Summarize how the periodic table is organized as it relates to valence electrons. 3.How reactive are the elements in group 1 the alkali metals? Why? 4. What is the difference between an ion and an atom? 5. What are polyatomic ions? 6. Are elements with 1-7 valence electrons stable or reactive? Why?

Bell Ringer #1 1.What are valence electrons? 2.Summarize how the periodic table is organized as it relates to valence electrons. 3.How reactive are the elements in group 1 – 7 the alkali metals? Why? 4. What is the difference between an ion and an atom? 5. What are polyatomic ions? 6. Are elements with 1-7 valence electrons stable or reactive? Why?

Education is not received. It is achieved.

A Mad Scientist’s Chemistry Presentation Atoms, Bonding, and the Periodic Table Chapter 5

Valence electrons are the electrons that have the highest energy level and are held most loosely. Which means what? The energy level determines the properties and bonding of atoms. Each element has a range of 1-8 valence electrons. Valence electrons are shown with electron dot diagram – each dot = 1 electron. Valence Electrons and Bonding

Chemical Bonds and Stability  Atoms of most elements are more stable when they have 8 valence electrons.  Atoms usually react in 2 ways 1.The number of valence electrons increases to 8 electrons. 2.The atom gives up loosely held valence electrons causing a chemical bond.

Chemical Bonds and Chemical Reactions  When atoms bond, electrons are transferred so chemical reaction occurs and new substances are made.

How the Periodic Table Works  Knowing the number of valence electrons is a clue as to how elements combine.  Take out your periodic table now  All of the elements in a group have similar properties because they have the SAME number of valence electrons  NOBLE GASES –all have 8 valence electrons except helium with 2 –most are stable with 8 electrons and most are unreactive other elements

Reactive Nonmetals and Metals HALOGENS Each atom has 7 valence electrons that react with elements who give up 1 electron. ALKALI METALS Alkali metals have only have 1 valence electron and very reactive.

OTHER METALS  Groups 3-12 have either 1, 2, or 3 valence electrons  How reactive a metal is depends on how easily its atoms lose valence electrons. OTHER NONMETALS *have either 4, 5, or 6 valence electrons *try to get to 8 valence electrons so they react easily

OTHER METALS METALLOIDS -have from 3 to 6 valence electrons -lose or share electrons HYDROGEN - only 1 valence electron - with the alkali metals but NOT a metal - very reactive

SECTION 2

Bell Ringer Read and study the Bell Ringer questions from yesterday Re-read section 1 of chapter 5….. P. 150 You may be having a quiz on this

Ions and Ionic Bonds Ions are atoms with an electric charge. If atom loses an electron then it becomes positive. If atom gains an electron then it becomes negative. Polyatomic ions are ions made of more than 1 atom.

Ions and Ionic Bonds continued  They can be either positive or negative.  The attraction between the 2 opposite charges is called ionic bond.  Ionic compounds have positive and negative ions (NaCl).

Chemical Formulas & Names A combination of symbols that shows the ratio of elements Always have balanced charges The number is called the subscript – it shows the ratio of elements

Chemical Formulas & Names continued The positive ion always comes first. If negative is single element then name ends in -ide (MgO = magnesium oxide). If negative ion is polyatomic then name ends in –ate or –ite (NH4NO3 = ammonium nitrate)

Properties of Ionic Compounds Ionic compounds are hard, brittle crystals High melting points Strong bonds – lots of energy to break apart Can conduct electricity in water –If ionic crystals dissolve in water, the bonds break apart moving in water so they will conduct electricity. Form in orderly, 3D way called a crystal

Bell Ringer #2 1.Name 3 properties of ionic compounds. 2.Which ion comes first? positive or negative 3.Table salt is NaCl. What is the ratio? 4.How do ionic compounds form?

Review

CHEMICAL FORMULAS 1.Turn to p. 159 in the book. 2.This will be turned and graded. 3. Using the chart, copy each chemical name and write the chemical formula. 1.Remember that the positive ion goes 1 st 2.The formula has to balance

1.lithium fluoride 2.sodium chloride 3.potassium iodide 4.calcium sulfide 5.magnesium carbonate 6.aluminum phosphate 7.ammonium oxide 8. lithium phosphate 9. ammonium sulfate 10. sodium carbonate 11. potassium sulfide 12. magnesium nitrate 13. calcium chloride 14. ammonium phosphate