1. Sodium (Na) - 11 Atomic Number = - - Atomic Mass = 23 - 12 neutrons+ + + +
12 neutrons
+11 protons 23 + - - + - - + + + + + P= N= E= 11 - - - 12 11

2. Oxygen (O) 8 Atomic Number = Atomic Mass = 16 - - - 8 neutrons+
8 neutrons
+ 8 protons 16 + + + - + + - + + P= N= E= 8 - 8 - - 8

3. Helium (He) 2 Atomic Number = Atomic Mass = 4 2 neutrons + 2 protons 4

4. Lithium (Li) 3 Atomic Number = Atomic Mass = 7 4 neutrons + 3 protons

5. Neon (Ne) 10 Atomic Number = - - Atomic Mass = 20 - 10 neutrons+ +
10 neutrons
+10 protons 20 + - + - + - - + + + P= N= E= 10 + + - 10 10 - -

6. Calcium (Ca) - - 20 Atomic Number = - - Atomic Mass = 40 - - -+ - +
20 neutrons
+20 protons 40 + + - - + - + - - + - + + + + + + + + + + + - + P= N= E= 20 + - 20 - - - 20 - -

7. Aluminum (Al) 13 Atomic Number = - - Atomic Mass = 27 - - -+ +
14 neutrons
+13 protons 27 + - - + + + - - - + + + + P= N= E= 13 + + + - 14 - - 13

8. Fluorine (F) 9 Atomic Number = - - Atomic Mass = 19 - 10 neutrons+ +
10 neutrons
+ 9 protons 19 + - + + - + - + + + P= N= E= 9 10 - 9 - -

9. Beryllium (Be) 4 Atomic Number = - Atomic Mass = 9 - 5 neutrons
+ 4 protons 9 + + + P= N= E= 4 + 5 - 4 -

10. Phosphorus (P) 15 Atomic Number = - - Atomic Mass = 31 - - -
16 neutrons
+15 protons 31 + + + + - + + + - - - - - + + + + P= N= E= 15 + + + + 16 - 15 - - -