Can you answer these MCQs? It's a part of my chemistry homework.

1) A crystal is most likely to have a low melting point, if it
a) is a macro molecule
b) is a crystal lattice
c) has delocalised valence electrons
d) has weak van der Waals' forces

2)Which two elements would form a covalent compound?
a) sodium and oxygen
b)copper and oxygen
c)carbon and oxygen
d)magnesium and oxygen

3) The elements P,Q AND R in the periodic table have consecutive increasing proton numbers. If element R is a noble gas, then the symbol for the ion of the element P is
a) P+
b) P2+
c)P-
d) P2-

Not sure about 1 but i would say D.
2) C
3) D

I think.