1. Chemical Bonding

2. Ions Ions- atoms with a net electrical charge.
An ion is formed when an atom has gained or lost an electron.
Ions that have gained an electron become negative.
Ions that have lost an electron become positive.

3. The Ionic Bond
Video

4. Helium, neon and argon are atoms which do not react with other atoms.
These are the Noble Gases on the Periodic table because of this.
Each of these gases has a full outer electron shell (orbit).
10p10n
18p22n
2p2n Ne He Ar
10 electrons
2 electrons
18 electrons
2,8
2,8,8

5. Sodium Na
11 protons
11p
12n
12 neutrons
11 electrons
2,8,1

6. Chlorine Cl
17 protons
17p
18n
18 Neutrons
17 electrons
2,8,7

7. + 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

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

9. + - The Ionic Bond Sodium atom Na Chlorine atom Cl Sodium ion (Na +)
Chlorine ion
(Cl -)
The sodium atom loses one electron to attain a complete outer shell and become a positive ion (Na +). The Chlorine atom gains one electron to attain a complete outer shell and become a negative ion (Cl –). Strong electrostatic forces attract the sodium and chlorine ions.

11. Ionic Compounds
Held together by strong electrostatic forces
Opposite charges attract
High melting points and boiling points
When melted or dissolved ionic compounds conduct electricity

12. Covalent Bonding
Video

13. Chlorine atom 2,8,7

14. 2 Chlorine atoms
Outer shells only

15. Chlorine molecule Cl2
Electrons shared
Each outer shell has 8 electrons
Forces (bonds) between atoms in the molecule very strong

16. Covalent bonds can be represented in 3 ways:

17. Chlorine Cl2 Cl Cl Cl Cl

18. Covalent Bonds:
Water H2O
Methane CH4
Ammonia NH3
Hydrogen H2
Hydrogen Chloride HCl
Oxygen O2

19. Oxygen O 16 8
Oxygen atom 2,6

20. 2 Oxygen atoms (outer shells only)
Double covalent bond O