2SAS 13-25 p. 130

13. a. row: periods
      b. column: group or family

14. Alkali metal family: Na: Sodium, K: Potassium

15. a. The noble gasses are located in column 18.
      b. One physical property that noble gasses sh are is that they are inert gasses
      c. One chemical property that noble gasses share is that they are unreactive/chemically inert.

16. a.  MgF
      b. GaP

17. potassium : 68⁰C

18. I would expect it to be lower because it weighs less than iodine, and it has a stronger attraction.

19.
C: 6 protons, 6 neutrons, 6 electrons
N: 7 protons, 7 neutrons, 7 electrons
Ca: 20 protons, 20 neutrons, 20 electrons
Pt: 78 protons, 117 neutrons, 78 electrons
U: 92 electrons, 146 neutrons, 92 electrons

20. a. Beryllium (Be): 4 protons, 5 neutrons, 4 electrons
      b. Nitrogen (N): 7 protons, 7 neutrons, 7 electrons
      c. Neon: (Ne): 10 protons, 10 neutrons, 10 electrons

21. The atom must have lost two electrons to give it a charge of 2+.

22. a. Carbon: 12.01
          Nitrogen: 14.01
          Calcium: 40.08
          Platinum: 195. 08
          Uranium: 238.03

b. The element Carbon has two isotopes because it has the same number of protons, but can have different numbers of neutrons.

23. It is not because we do not know the number of protons, electrons, or neutrons, and we also don't know what similar characteristics it has has with other elements on the table.

24. An electron has the least mass of the three; it weighs so little that scientist don't count its weight when founding the atomic weight of an element.

25. a: 12
      b: 12
      c: 12
      d: 13
      e: 12
      f: 14