Answer: D. Made of only one kind of atom
Explanation:A compound forms whenever two or more atoms form chemical bonds with each other.
Energy would be needed to cause an electron to be a valence electron.
Mass cannot be created nor destroyed as the law of conservation of mass states.
Pulled apart (moved with the magnetic force)
Answer:
Equilibrium concentration of
is 
Explanation:
Construct an ICE table to calculate changes in concentration at equilibrium.

I: 0.1 0 0
C: -x +x +x
E: 0.1-x x x
= 
(species inside third bracket represent equilibrium concentrations)

or, 
So,
M
or, 
So, equilibrium concentration of
=
=x=