Section A Summary: 13-25

13. Features of the periodic table:

a.    Period

b.    Group or family

14. Potassium (K) and Rubidium (Rb)

15. Noble gas family:

a.    Noble gases are located in the far right column on the periodic table.

b.    Noble gases are all gases at room temperature.

c.    Noble gases are nonreactive with other elements.

16. BeCl2 and AlN

a.    MgF2

b.    GaP

17. By taking the averages of sodium and rubidium’s melting points, we find that the melting point of potassium should be around 68.5 °C

18.I would expect the boiling point of chlorine to be lower than iodine’s because iodine has a higher atomic number than chlorine. Based off the graphs we made about the relationships between the properties of elements and their atomic numbers, then iodine’s boiling point should be higher.

19.

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.On paper

21. Instead of gaining two protons, the lead has lost two electrons. Ions are not formed from losing or gaining protons, but electrons.

22. Element table:

a.    C(1) =12; C(2) =13; Ca =41; Pt =195; U =238

b.    Carbon has two isotopes in the table.

23. No, the mass number is not enough to claim that there is a new element. This is because we need to know which group it fits in, and what other characteristics it has. Just giving the mass number does not give proof that a new element is out there.

24.The mass of an electron is 1/2000 the mass of a proton or neutron.

25.Mg-24: 12 protons, 12 neutrons

Mg-25: 12 protons, 13 neutrons

Mg-26: 12 protons, 14 neutrons