Unit 2: Atoms and Elements Lesson 2: Periodic Table

Bell Work List the Atomic theories in order and what they discovered.

SC Standards 7.P.2.A Conceptual Understanding: All substances are composed of one or more elements. Elements are pure substances which contain only one kind of atom. The periodic table organizes these elements based on similar properties. Compounds are substances composed of two or more elements. Chemical formulas can be used to describe compounds. 7.P.2A.2: Obtain and use information about elements (including chemical symbol, atomic number, atomic mass, and group/family) to describe the organization of the periodic table. S.1A.8: Obtain and evaluate scientific information to (1) answer questions, (2) explain or describe phenomena, (3) develop models, (4) evaluate hypotheses, explanations, claims, or designs or (5) identify and/or fill gaps in knowledge. Communicate using the conventions and expectations of scientific writing or oral presentations by (1) evaluating grade-appropriate primary or secondary scientific literature, or (2) reporting the results of student experimental investigations.

Today’s Objectives (SWBAT) Obtain and use information from secondary sources about elements to describe the organization of the periodic table.

Today’s Agenda Bell Work Review Quiz Take Quiz Notes on Elements

The Father of the Periodic Table—Dimitri Mendeleev Mendeleev was the first scientist to notice the relationship between the elements Arranged his periodic table by atomic mass 1869 1st Periodic Table 1871 2nd Edition Published Protons give elements their character

What does the information in the box tell me? 1 H 1.008 Chemical Symbol: found between the atomic number and atomic mass Contains 1 to 2 letters of the English or Latin names Atomic Number = # of protons Atomic Mass = # of protons plus neutrons

Use of the Periodic Table Atomic number increases from left to right Class of elements Metals, nonmetals, and metalloids Properties can be predicted from the location of the element

The Periodic Table Column = Group or Family 18 columns on the Periodic Table Row = Period 7 rows on the Periodic Table

Periods •Each row is called a “period” •The elements in each period have the same number of energy levels 1st Period = 1 E. Level 2nd Period = 2 E. Levels 3rd Period = 3 E. Levels 4th Period = 4 E. Levels 5th Period = 5 E. Levels 6th Period = 6 E. Levels 7th Period = 7 E. Levels

Groups •Each column is called a “group” •Each element in a group has the same number of electrons in their outermost energy level (valence electrons) Group 1 = 1 electron Except for He, it has 2 electrons Group 2 = 2 electrons 4 Group 8 = 8 electrons Middle School Science Image: Chem4kids.com

Lesson 2: Periodic Table Day 2

Bell Work Who came up with the Periodic table? What is the difference between a period and a group?

Valence Electrons Have highest energy Involved in chemical bonding Number of valence electron determines chemical properties

Electron Dot Diagrams Each dot represents an electron Each element has a specific number of valence electrons 1-8 valence electrons

Bonding More stable is they have 8 valence electrons Valence electrons can be shared or transferred Chemical bonds Attraction that holds atoms together due to arrangement of electrons between elements

Metals, Nonmetals, and Semi-metals Nonmetals are on the right of the stair-step Only nonmetal on the metal side Metals are to the left of the stair- step Semi-metals, “metalloids,” touch the stair-step

Periodic Table

Noble Gasses Group 18 8 Valence Electrons Stable-nonreactive

Metals Elements in the blue section React by losing their valence electrons Decrease from left to right Alkali Metals Most reactive Explode in water

Nonmetals Orange section Gain or share electrons Combine with metals by gaining electrons React easily with other elements 7 valence electrons

Metalloids Lie along a zigzag line Between metals and nonmetals Has properties of both