Homework 7/9

Page 130 #13-25

13. A) Period

B) Group

14. Magnesium (Mg) and Calcium (Ca)

15. A) Column 18

B) Odorless, Colorless, and Tasteless

C) They don’t react

16. A) MgF₂

B) GaP

17.  98+39=137…137/2=68.5 is the melting point

18. Chlorine’s melting point would be lower than iodine’s because the elements that have higher atomic weights have higher boiling points than those with lower atomic weights, and chlorine has a higher atomic weight than iodine.

19. 

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

20.A) 4 protons, 4-5 neutrons, 4 electrons

B) 7 protons, 7-8 neutrons, 7 electrons

C) 10 protons, 10-11 neutrons, 10 electrons

21. A lead ion with a 2+ charge was formed, which means that the atom must have lost two electrons. When the electrons get lost, there are more protons remaining in the atom. This results in the formation of cations.

22. A) Carbon: 13

Nitrogen: 14

Calcium: 41

Platinum: 195

Uranium: 238

B) Carbon and Platinum has 2 isotopes

23.No, not enough information is given to be sufficient because it does not provide us with the atomic number or the atomic mass. If those were provided the scientist would be able to distinguish properties of the element faster.

24. The mass of an electron is significantly lower than the mass of protons or neutrons. It is about 1/2000 of the weight of a proton or neutron.

25.

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