Physical Science

Date: July 19, 2014

Objective: I can predict the oxidation number and number of valence electrons for an element as well as draw Lewis dot diagrams. To Do:• Complete Catalyst (5 minutes) • Have binder ready & periodic table out

Catalyst: Review

Subatomic

Particle

Charge

Location Size

protonelectronneutron

positivenegativeneutral

Inside nucleus

Inside nucleus

outside nucleus

1 amu

1 amu

1/2000

amu

Catalyst: Review② Compare a period to a group on

the periodic table.

• A period is a row on the periodic table• There are 7 periods• A group is a vertical column • There are 8 representative groups

• Both contain elements and provide useful information about atoms

Catalyst: Review

Periods

Groups

Catalyst: Review

③ What can the period or row tell you when drawing Bohr models?

• A period or row tells you how many rings or shells to draw on a Bohr model.

Catalyst: Review

④ Sodium

⑤ Carbon

Remember:• 1st ring: 2

e-• 2nd ring: 8

e-• 3rd ring: 18

e-

Today’s Objective

Objective: I can predict the oxidation number and number of valence electrons for an element as well as draw Lewis dot diagrams.

VocabularyValence electron: An electron on the outermost energy level in an atom 1

valence e-

4 valence

e-

Valence electrons• Atoms in the same family have

the same # of valence electrons

• Elements in the same family have similar properties

Valence electrons1

2 3 4 5 6 78Label your periodic tables as

shown here:

popcorn• We will play popcorn around the

classroom

• We will ask questions about valence electrons

• For example, “How many valence electrons does Nitrogen have?”

• If you answer correctly, you may choose the next student to ask a question to

Vocabulary• Oxidation Number: Refers to the

number of electrons lost or gained during chemical bonding

• When metals and nonmetals form compounds, they lose or gain valence electrons

Vocabulary

• Ionic Bond: A bond between a metal and a nonmetal

• Ion: An atom with a positive or negative charge

Ions• An ion is an atom that has a positive

or negative electric charge • Represented by the plus or minus sign

Na+• Plus sign tells

me that this sodium atom gave an electron away

Oxidation #+1

+2 +3 +-4 -3 -2 -10Label your periodic tables as

shown here:

Oxidation #

• Metals have a positive charge because they lose electrons

• Nonmetals have a negative charge because they gain electrons

Lewis dot diagrams

• Bohr diagrams help us see electron configurations for atoms

• Bohr diagrams help us understand reactivity

• Lewis dot diagrams show valence electrons only

1. Write the chemical symbol 2. Find the # of valence electrons (group #)3. Draw the valence electrons (cross method)

Drawing Electron dot diagrams

Valence electrons = 7

Cl

Examples:

Practice• Using your dry erase board, draw dot

diagrams for the element I call out

• When I say to, hold up your dry erase board

• Work independently

Activity• Complete the Mix & Match Activity

with your table partner

• When finished, raise your hand and I will check your work

• You have 25 minutes to complete correctly

• Pick-up the Periodic Table Challenge when finished

Exit ticket• Complete the Exit Ticket

• You may use your periodic table

• Keep eyes on your own paper

• 10 minutes