1. Warm-up An ion is an atom that gained or lost electrons.
Which of the following atoms is an ion: the left or right atom? What is the total charge of the ion? - - - + + + + + + + + - - -

2. Rules of Ions
Rule 1: Opposite charges attract. “+” attracts “-” - +

3. Rules of Ions Rule 1: Opposite charges attract. “+” attracts “-”
Rule 2: Charge = Protons - Electrons
+4 protons
- 4 electrons
0 charge
+4 protons
3 electrons
+1 charge
+4 protons
2 electrons
+2 charge

4. Rules of Ions Rule 1: Opposite charges attract. “+” attracts “-”
Rule 2: Charge = Protons – Electrons
Rule 3: Valence electrons = Group # (1A to 8B)

5. Rules of Ions Rule 1: Opposite charges attract. “+” attracts “-”
Rule 2: Charge = Protons – Electrons
Rule 3: Valence electrons = Group # (1A to 8B)
Rule 4: Atoms try to gain or lose electrons have a full outer shell.
Lose electrons Gain electrons

6. Ionization
The process of when an atom gains or loses electrons to become an ion. -
+4 protons
- 4 electrons
0 charge -
+4 protons
3 electrons
+1 charge + + + + -
+4 protons
2 electrons
+2 charge -

7. Ionization
The process of when an atom gains or loses electrons to become an ion. -
+8 protons
- 8 electrons
0 charge - - - +
+8 protons
9 electrons
-1 charge + + - - + + + + + - - -
+8 protons
10 electrons
-2 charge -

8. Electronegativity How “greedy” an atom is for electrons.
Strong electronegativity = greedy, steals electrons
Weak electronegativity = not greedy, gives away electrons
Give away electrons
Steal electrons