1. Introduction to Chemical Bonding
Atoms seldom exist as independent particles in nature. Nearly all substances consists of combinations of atoms that are held together by chemical bonds.
A chemical bond is a mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together.

2. Why are most atoms chemically bonded to each other?
Most atoms are less stable existing by themselves. By bonding with each other, atoms decrease their energy creating a more stable arrangement.

3. Octet Rule
Chemical Compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of (8) valence electrons.
Each atom wants to achieve the same arrangement as the Noble Gases.
Which Noble Gas is stable with only 2 valence electrons?

4. Three Major Types of Chemical Bonding
1. Ionic Bonding
2. Covalent Bonding
3. Metallic Bonding

5. gives one or more electrons so both atoms end up with
IONIC BONDING
When an atom of a metal
gives one or more electrons
to a non-metal
so both atoms end up with
8 valence electrons

6. IONIC BOND FORMATION Non-Metal Metal
Neutral atoms come near each other. Electron(s) are transferred from the Metal atom to the Non-metal atom. They stick together because of electrostatic forces, like magnets.

7. There are 2 Types of Ions:
IONIC BONDING
IONS – any atom with more or less electrons than its
Neutral atom.
There are 2 Types of Ions:
Cations – positively charged ions
Anions – negatively charged ions

8. Positive Ions are formed when…
Metals tend to lose electrons to become stable, and they are called………
CATIONS = Na
11 p
10 e + -
to become sodium ion + -
11 p
11 e Na
Normal sodium atom - 1e
loses one electron

9. Ionic Bond Video

10. Cations
When sodium forms a compound with a non-metal - it is called a sodium ion.
It is written as Na +1, meaning that it loses one electron to become stable.
The +1 symbol means it
has lost one electron

11. + The Sodium atom has 1 Electron in it’s outer shell.Na
e.c. 2,8,1
Atom +
The Sodium loses 1 electron to leave a complete outer shell.
It is now a Sodium ion with a charge of 1 +
(Na +)
e.c. (2,8)+
Ion

13. 1. How many valence electrons does Mg have?
2. How many electrons does it need in its highest energy level to be stable?
3. What does the Mg atom do in order to become stable? (Achieve the same configuration as a Noble Gas?)

14. ANSWERS
1) 12
2) 8 (octet rule)
3) lose 2 electrons

15. to become a chloride ion
Negative Ions
Nonmetals will tend to gain electrons to become stable, and they are called
ANIONS
17 p
17 e + - Cl
Normal chlorine atom = Cl
17 p
18 e + -
to become a chloride ion + 1e -
gains an electron

16. - The Chlorine atom has 7 electrons in it’s outer shell.Cl
e.c. 2,8,7
Atom -
(Cl - )
The Chlorine gains 1 electron to gain a complete outer shell.
It is now a Chlorine ion with a charge of 1 -
e.c. (2,8,8)-
Ion

17. S2- is called a sulfide ion gains two electrons to become stable
ANIONS
S2- is called a sulfide ion
The 2- symbol means it
gains two electrons to become stable

18. Classwork / Homework
Ionic Bonds Worksheet

19. There is another special group of anions, called Polyatomic Ions

20. (CO3)2---carbonate ion (PO4)3--- phosphate ion
Polyatomic Ions – Pg. 226
A group of atoms that act like one anion and carry a negative charge.
(CO3)2---carbonate ion
(PO4)3--- phosphate ion

21. Polyatomic Ions -EXCEPTION
The one exception is NH4+1 (ammonium), which is a cation and carries a positive charge.

22. Na and (SO4)2- Polyatomic Ions
POLYATOMIC IONS ACT JUST LIKE ANY OTHER NEGATIVE ION WHEN BONDING
Na and (SO4)2-
What is the metal?
What is the non-metal?
What charge does (SO4) have ?

23. Name and give the charge of the following Polyatomic Ions
Ba (NO3)-1
Mg(PO4)3-
Li(ClO)-1

24. ANSWERS
Barium nitrate
Magnesium phosphate
Lithium hypochlorite

25. Properties of Ionic Compounds
At room temperature, most ionic compounds are crystalline solids.
Ionic compounds are brittle, and shatter if they are hit.
Because of their strong electrostatic attractions, ionic compounds are very strong and have high boiling and melting points.
When melted or dissolved, ionic compounds conduct electricity.