4 Physical Science questions, please? =]?

[hyun-su]

I'm filling out my study guide for this class and would really like to be studying the right answers haha!

1. In a polar covalent bond,
a.) electrons are shared equally between atoms.
b.) a cation is bonded to an anion.
c.) electrons are transferred between atoms.
d.) electrons are not shared equally with atoms.

2. Because water molecules are polar, and carbon dioxide molecules are nonpolar,
a.) water has a lower boiling point than carbon dioxide does.
b.) attractions between water molecules are weaker than attractions between
carbon dioxide molecules.
c.) carbon dioxide cannot exist as a solid.
d.) water has a higher boiling point than carbon dioxide does.

Fill in the blank:
9. The pattern of repeating properties of elements revealed in the periodic table
is known as the _____________.

10. To determine the atomic mass of an element, you would take a(n) ______
average of isotopes that make up that element.

[lorimar]

I think it's a,a, periodic law or something, and I don't understand question 10