Homework Assignment 13

2SAS #13-25 p. 130

13. Another name for:

• Row: period
• Column: group

14. Magnesium (Mg) and Calcium (Ca)

15. Consider the noble gas family:

• a. Column 18
• b. They are all odorless, colorless, and tasteless (physical property)
• c. They all do not react chemically (chemical property)

16. 

• a. MgF2
• b. GaP

17. Since potassium is in between sodium and rubidium on the periodic table, its boiling point would be 68.5 because 98 + 39 / 2 = 68.5.

18. I would expect chlorine's boiling point to be lower than iodine's because chlorine's atomic weight is lower, therefore its boiling point probably is as well.

19. Electrically neutral atoms:

Element Symbol	Number of Protons	Number of Neutrons	Number of Electrons
C	6	6	6
C	6	7	6
Ca	20	21	20
Pt	78	117	78
U	92	146	92

20. Number of protons, neutrons, and electrons in an atom of the following:

• Beryllium: 4 protons/electrons, 4-5 neutrons
• Nitrogen: 7 protons/electrons, 7-8 neutrons
• Neon: 10 protons/electrons, 10-11 neutrons

21. Even though the charge of the ion is 2+, the lead atom must have lost 2 electrons instead of gained because now there are 2 more protons (positive ions) than electrons (negative ions).

22. #19 table:

• a. Mass for each number in the table: 
• Carbon: 12
• Calcium: 41
• Platinum: 195
• Uranium: 238
• b. Calcium has 2 isotopes in the table.

23. By knowing an element's mass number, that information is not sufficient enough to claim the discovery of a new element. One must be familiar with the atomic weight or number in order to distinguish physical and chemical properties.

24. The mass of an electron is way less than the masses of a proton and a neutron.

25. Isotopes of Magnesium Table:

Isotope Symbol	Mass Number	Number of Protons	Number of Neutrons
Mg-24	24	12	12
Mg-25	25	12	13
Mg-26	26	12	14