2SAS #13-25 p.130

13. Row- period

      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. I estimate the melting point of potassium to be 59 degrees C. 

18. I would expect the boiling point of Chlorine to be lower because it has a smaller atomic mass, which means that it weighs less. 

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 correction would be that the lead atom must have lost two protons in order to make the ion. 

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 know what the scientist is measuring the mass of. 

24. The electron has the least mass compared to the mass of the proton and neutron.

25. 24- 12, 12

      25- 12, 13

      26- 12, 14