Unit 3 Day 6

Valence Electrons, Lewis Structure and

Oxidation NumbersYou will need a chromebook, white board,

marker and towel

Warm-Up: Partner Work(1) How many electrons can an orbital contain? _________

(2) What is the symbol of the element with the following electron configuration? 1s2 2s2 2p6 3s2 3p5

(3) What is the noble gas configuration for Tin (Sn)? _______________________________________

(4) Which of the following would have an outermost electron configuration of ns2 np4?

(a) Pb (b) Zr (c) Mo (d) Se

(5) What is the total number of electrons in “s” orbitals in a germanium atom? ______________

(6) How many electrons are in the highest energy “p” orbitals of a bromine atom? __________

(7) Which of the following have the SAME electron configurations?

A. Na -1 and Ne B. Mg2+ and Ar C. Cl-1 and Li+1 D. Ca+1 and Ar E. K+1 and Ar

(8) How many UNPAIRED electrons are in the ground state of oxygen? __________________

(9) List the following orbitals in order of INCREASING energy within an atom:

5f , 1s, 4p, 4s, 3d, 7s,

Partner Work(1) How many electrons can an orbital contain? 2

(2) What is the symbol of the element with the following electron configuration? Cl

(3) What is the noble gas configuration for Tin (Sn)? [Kr] 5s24d105d2

(4) Which of the following would have an outermost electron configuration of ns2 np4?

(a) Pb (b) Zr (c) Mo (d) Se

(5) What is the total number of electrons in “s” orbitals in a germanium atom? 8

(6) How many electrons are in the highest energy “p” orbitals of a bromine atom? 5

(7) Which of the following have the SAME electron configurations?

A. Na -1 and Ne B. Mg2+ and Ar C. Cl-1 and Li+1 D. Ca+1 and Ar E. K+1 and Ar

(8) How many UNPAIRED electrons are in the ground state of oxygen? 2

(9) List the following orbitals in order of INCREASING energy within an atom:

5f , 1s, 4p, 4s, 3d, 7s, 1s, 4s, 3d, 4p, 7s, 5f

HOMEWORK CHECK

Following 3 Slides

EXTENSION Practicehttp://www.sciencegeek.net/Chemistry/Quizzes/

ElectronNotations/?_sm_au_=iVVHMPrvVjBTrM

QF

Objectives• Determine the number of valence electrons of an element.

• Draw a Lewis dot diagram for a given atom

• Determine the charge of an ion based on its location on the periodic table.

Valence Electrons• Valence electrons: the electrons in the highest energy

level(aka : outermost energy level or outermost ‘shell’) that are responsible for bonding and forming ions.

Write the Noble Gas Notation for Oxygen:

_________________________________

What’s the highest energy level represented?__________

How many electrons are in the highest energy level?______

Thus, oxygen has how many valence electrons?______

Valence Electrons• Valence electrons: the electrons in the highest energy

level(aka : outermost energy level or outermost ‘shell’) that are responsible for bonding and forming ions.

Noble Gas Notation for Oxygen is:

[He] 2s22p4

What’s the highest energy level represented? 2How many electrons are in the highest energy level? 6

Thus oxygen has how many valence electrons? 6

Val e- Discovery Activity

• Get into your learning teams• on a whiteboard write

• the symbol for your element• the Noble Gas Notation for your

assigned element• determine the number of valence

electrons you have and write it on your board

• when instructed, sit with other elements that are in your family

On your whiteboard, match the following elements with their valence electrons.1. S A. 1

2. K B. 2

3. Ga C. 3

4. I D. 6

5. Cu E. 7

On your whiteboard, match the following elements with their valence electrons.1. S A. 1

2. K B. 2

3. Ga C. 3

4. I D. 6

5. Cu E. 7

Consider this!

Why do all transition metals have the same number of

valence electrons??

Return to your seats with a whiteboard, rag, and marker

Lewis Dot Diagrams• Visually expresses the number of

valence electrons.

• Step 1: Write the symbol for the element

• Step 2. Pretend the symbol is in a box and draw a dot on each side for every valence electron (one per side)

C = [He] 2s2 2p2

Example• Draw the Lewis dot structure for Oxygen.

Example• Draw the Lewis dot structure for Ne.

Example• Draw the Lewis dot structure for Cu.

You try!Draw the Lewis dot diagrams for the following on your whiteboard:

• Ca

• Fe

• I

What about ions??• Remember: An ion forms when atoms gain or lose

electrons.

• They do this to become like noble gases who have a filled outer energy level.

• Octet Rule: atoms need 8 valence electrons to be happy.• Exception is Hydrogen because he only wants 2,

note his highest energy level is still full!

Exploring Oxidation Numbers

• Click the link above and MAKE A COPY

• Highlight elements that GAIN the same number of electrons a particular color

• Highlight elements that LOSE the same number of electrons a particular color

Can I get your Oxidation number?

• using the previously assigned element write the following on your whiteboard:• symbol• # electrons lost/gained• oxidation number

• when instructed, find and sit with other elements that are in your family

• How does your oxidation number relate to the number of your valence electrons?

RETURN TO YOUR SEAT

Groups or Families form identical ions

LABEL:VALENCE ELECTRONS

OXIDATION NUMBER (CHARGE)

LEWIS DOT STRUCTURE

You TryOn Your Whiteboard...Determine the charges of the following ions.

• Bromine (Br)

• Rubidium (Rb)

• Neon (Ne)

• Sulfur (S)

EXIT TIX

Al Ca+2 I-

# Valence Electrons?

Write the Noble Gas Config of the atom or ion

Write the Lewis Dot Structure for the Ion

CLASSWORK/HOMEWORK

Prepare for QUIZ tomorrow on -

Bohr Model(p. 8 Ref Tables), EMS, Orbital Notation, Electron Configuration, Nobel Gas Configuration