1. How do you know how many valence electrons an atom has?

Day 2 3-20

Notation used to show an abbreviated version of an elements valence electron arrangement

H

F

O

Notation used to show an abbreviated version of an elements valence electron arrangement

First determine number of valence electrons.

Valence electrons are represented with dots around the element’s symbol.

H

F

O

Notation used to show an abbreviated version of an elements valence electron arrangement

2 e-s. can fit per side (you can think of each side of the symbol as an orbital)

H

F

O

H

F

O

In order to bond an element must be able to give AND take an electron.

In order for a bond to form an atom must be able to “give” an electron and “take one”

F Both can bond once

H

Examples:Sodium = can bond ____

Phosphorous = can bond ____

Aluminum = can bond ____

Fluorine = can bond ____

You Practice:

N =

B =

C =

Lewis Dot Structure Can Bond?

Using Lewis dots to represent bonds (Lewis dots for compounds):

Na Cl

Na ClShared electrons (bonds) are represented with a line

Suggested Steps:1. Do each individual Lewis dot structure and determine how many times each element can bond2. Look for ways to make everyone happy3. Lewis dot structure must match formula!!!

B. Practice:

potassium and fluorine bond

magnesium and chlorine bond

lithium and oxygen bond

hydrogen and oxygen bond

READ section 7.1 and complete #s 1-8 on page 199

-Due Friday 3-27

BINDERS!!!

1. The halogens all have __ valence which means they all want to ______________.

Day 6 3-26

7

gain one electron

How do elements combine to form compounds?

Electrostatic Force – an interaction between charged particles

Opposites –

Like charges –

Attract

Repel

What happens when atoms collide?Valence electrons interact.

Valence electrons dictate

reactivity!

Chemical bond – A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds them together … electrostatic force

Opposites Attract!!!

Nuclei = _______________ charge

Electrons = _______________ charge

positive

negative

Holding it all together

But Why Bond at all?

Atoms want a full set of valence electrons (8) and they can share (bond) to

get them!!!

~ octet rule

Why bonds and ions? Achieving electrical and energetic stability.Lone electrons – high potential energy - BAD

Br

Electron pairs – stable - Good

3 main bond types:• Ionic

• Polar covalent

• Nonpolar covalent

Electrostatic Force – an interaction between charged particles

Opposites –

Like charges –

Attract

Repel

Cation – positive ion

Anion – negative ion

Ions – charged particles

Collision – Ions

Br

LiBANG

Br(-)

(+)

Li

Br

LiBANG

BrLi

But they don’t separate … WHY? + -

Electrostatic Force

Ionic bonds – Chemical bonds that result from the electrical attraction between large numbers of cations and anions

Cation – ?

Anion – ?

Atoms Only transfer elecs. (form ions) when one atom has a very strong attraction for elecs. (wants them a lot more)

Electronegativity – measure of atom’s ability to attract electrons

Electronegativity

Electronegativity P. T. (page 181)

Ionic bonds most commonly form between metals and

nonmetals!

Ionic bonds are made up of charged pieces (ions)

Ions can be made up of one element or a combination of elements (polyatomic ions)

Ionic Compounds:

high melting points – strong bonds

Brittle

dissolve in water to produce mobile ions – good conductors

1. Draw the Lewis dot structure for chlorine.

Day 1 3-27

2. Draw the Lewis dot structure for oxygen – use your notes packet if needed.

READ section 7.1 and complete #s 1-8 on page 199

-Due Friday 3-27

BINDERS!!!

Quarterly Exam = Tuesday 3-31

http://www.youtube.com/watch?v=QqjcCvzWwww

http://www.youtube.com/watch?v=bK9nMHTLhmk

http://www.youtube.com/watch?v=BCYrNU-7SfA

Electrostatic Forces

L A B