The mass of an atom is
a.)distributed uniformly throughout the atomic sphere.
b.)concentrated in the electrons.
c.)divided equally between the nucleus and the electrons.
d.)concentrated in the nucleus.

I'd say d.) Concentrated in the nucleus.

This is because Nucleus consists of protons and neutrons; contributing to some mass, whereas Electron's mass is almost negligible ( 9.1 x 10^-31 kg) 

Hope this answers your question!

It won't lose or gain electrons if it's a covalent bond it shares the electrons with another atom or atoms. if it is an ionic bond it will lose the 3 electrons on the outer shell and become a positively charged ion.  credit goes to @sunshinebaby of answers.yahoo.com.

Rain is pulled by gravity which is a non contact force