HW #2

2SAS #13-25:

13. a) Row: period    b) Column: group

14. Sodium (N) and Potassium (K). 

15. (a) The noble gases are located in column 18.    (b) They are all odorless.    (c) They do not chemically react.

16. (a) MgF2    (b) GaP

17.  69 degrees C. 

18. I think the boiling point of Chlorine is lower because it has a smaller atomic mass.

19. A. C

      B. N

      C. 20

      D. 20 

      E. Pt

      F. 78

      G. 92

      H. 92

20. (a) 4 protons, 4 electrons, 5 neutrons   (b) 7 protons, 7 electrons,7 neutrons   (c) 10 protons, 10 electrons, 10 neutrons

21. The lead atom must have gained two electrons in order to make the ion because you can not loose or gain protons.

22. A. Carbon: 12.01

           Nitrogen: 14.01

           Calcium: 40.08

           Platinum: 195.08

           Uranium: 238.03 

      B. Platinum and Uranium both have two isotopes. 

23. No, this is not enough to justify the claim of the discovery of a new element because you do not have enough information to determine the elements physical or chemical properties.

24. The electron 1/2000 the moss of the proton and neutron.

25. 24- 24, 12, 12

      25- 25, 12, 13

      26- 26, 12, 14