The Structure of Matter

1

• The Structure of Matter
• How atoms form compounds

2
Compounds

• Formed when two or more elements combine
• Must make a chemical change
• New properties
• Atoms from the different elements form bonds
• Chemical Bond- the attractive force that holds
  different atoms or ions together

3
Compounds

• Every compound has a specific ratio of atoms
• Written as a chemical formula
• Examples H2O, C12H22O11, NaCl
• The ratio is the same every time, every where
• Different ratio means a different compound

4
Chemical Bonding

• When the valence electrons interact
• Atoms react to be more stable. They do this by
  filling their outermost energy levels
• Two ways to do this
• Share electrons
• Transfer electrons

5
Electron Dot diagrams

• A way of keeping track of valence electrons.
• How to write them
• Write the symbol.
• Put one dot for each valence electron
• Dont pair up until they have to

X
6
The Electron Dot diagram for Nitrogen

• Nitrogen has 5 valence electrons.
• First we write the symbol.

N

• Then add 1 electron at a time to each side.

• Until they are forced to pair up.

7
Write the electron dot diagram for

• Na
• C
• O
• Ne

8
Ionic Bonding

• Anions (negative) and Cations (positive) are held
  together by opposite charges (a metal and a
  non-metal element).
• The bond is formed through the transfer of
  electrons.
• Electrons are transferred to fill their outer
  levels

9
Electron Configurations for Cations

• Metals lose electrons to fill their outer levels
• They make positive ions.

10
Electron Dots For Cations

• Metals will have few valence electrons

Ca
11
Electron Dots For Cations

• Metals will have few valence electrons
• These will come off

Ca
12
Electron Dots For Cations

• Metals will have few valence electrons
• These will come off
• Forming positive ions

Ca2
13
Electron Configurations for Anions

• Nonmetals gain electrons to fill their outer
  levels
• They make negative ions.

14
Electron Dots For Anions

• Nonmetals will have many valence .electrons.
• They will gain electrons to fill outer shell.

P
P-3
15
Stable Arrangements

• All atoms react to fill their outer levels
• Noble gases have full outer energy levels.
• 8 valence electrons .
• Also called the octet rule.

Ar
16
Ionic Bonding

• Ionic Chemical Bonding
• When ionic compounds form, the charges of the
  ions must equal zero. (the molecule has no
  overall charge)

17
Ionic Bonding
Na
Cl
18
Ionic Bonding
Na
Cl-
19
Ionic Bonding

• All the electrons must be accounted for!

Ca
P
20
Ionic Bonding
Ca
P
21
Ionic Bonding
Ca2
P
22
Ionic Bonding
Ca2
P
Ca
23
Ionic Bonding
Ca2
P-3
Ca
24
Ionic Bonding
Ca2
P-3
Ca
P
25
Ionic Bonding
Ca2
P-3
Ca2
P
26
Ionic Bonding
Ca
Ca2
P-3
Ca2
P
27
Ionic Bonding
Ca
Ca2
P-3
Ca2
P
28
Ionic Bonding
Ca2
Ca2
P-3
Ca2
P-3
29
Ionic Bonding
Ca3P2
Chemical Formula
30
Covalent bonds

• Nonmetals hold onto their valence electrons.
• They cant give away electrons to bond.
• Still want full outer level (remember octet rule)
• Get it by sharing valence electrons with each
  other.
• By sharing both atoms get to count the electrons
  toward noble gas configuration.

31
Covalent bonding

• Fluorine has seven valence electrons

32
Covalent bonding

• Fluorine has seven valence electrons
• A second atom also has seven
• By sharing electrons

33
Covalent bonding

• Fluorine has seven valence electrons
• A second atom also has seven
• By sharing electrons

34
Covalent bonding

• Fluorine has seven valence electrons
• A second atom also has seven
• By sharing electrons
• Both Fluorine atoms end up with full energy level

35
Covalent bonding

• Fluorine has seven valence electrons
• A second atom also has seven
• By sharing electrons
• Both Fluorine atoms end up with full energy level

F
F
8 Valence electrons
36
Covalent bonding

• Fluorine has seven valence electrons
• A second atom also has seven
• By sharing electrons
• Both Fluorine atoms end up with full energy level

F
F
8 Valence electrons
37
Water

• Each hydrogen has 1 valence electron
• Each hydrogen wants 1 more
• The oxygen has 6 valence electrons
• The oxygen wants 2 more
• They share to make each other happy

38
Water

• Put the pieces together
• The first hydrogen is happy (outer electron cloud
  is filled)
• The oxygen still wants one more

H
39
Water

• The second hydrogen attaches
• Every atom has full energy levels

H
H