1. Kinds of Chemical Bonds
Unit 3

2. To fill their outer energy levels with electrons.
Why do atoms combine?
To fill their outer energy levels with electrons.
To become chemically stable like the Noble Gases.

3. What are the 3 ways electrons move between atoms?
1.) Giving them (lose) [+]
2.) Taking them (gain) [-]
3.) Sharing them [NC]

4. By giving away or taking electrons, it sets up an unbalance of charges.
Losing / Giving
Gaining / Taking E P P E

5. Ion An electrically charged atom.
* can be positively [+] or negatively [-] charged

6. Superscript Means “written above”.
* tells how many electrons are unbalanced and the charge of the ion
* A.K.A.: oxidation number
* ex.: Ca2+ : O2- : K+ : F-

7. Ionic Bond
The force of attraction between the opposite charges of ions.
* smallest part of an ionic bond is an ION

8. » The Positive to Negative Attraction
Ionic Bond
» The Positive to Negative Attraction
Na Cℓ
= Na+ + Cℓ- = NaCℓ
Mg S
= Mg2+ + S2- = MgS

9. Covalent Bond
The force of attraction created when atoms share electrons.
* smallest part of a covalent bond is a MOLECULE

10. Covalent Bond Extra electrons buzz around both atoms.
No electrical charge because no electrons change location permanently.

11. Atoms in a covalent bond do not always share the extra electrons equally.
* the larger atom will be in possession of the electrons most of the time

12. Polar Molecule A molecule that has a positive and a negative end.
* “Polar” means having opposite ends
* H2O is a polar molecule

13. Non-Polar Molecule
A molecule that does not have oppositely charged ends.
* atoms share electrons equally
* “Diatomic 7” = H2 N2 O2 F2
Cℓ2
Br2 I2

14. Most Ionic bonded compounds are crystalline solids with high melting points.
* salt

15. Most Covalent bonded compounds are liquids or gases at room temperature.
* water
* carbon dioxide

16. You can tell the type of bond by looking at the elements in the compound.
* metal + non-metal = Ionic
* non-metal + non-metal = Covalent
* metal + metal = Alloy [no real bond]

17. The End