Question

How are energy and mass connected during the formation of an atom?

Answer 1

Energy is absorbed so, the mass is increased. 
energy is released so, the mass is increased

Answer 2

Answer:

$E=m*c^2$

Explanation:

The equation of special relativity.

So you can see that mass and energy are proportional to each other. E - is energy, m - is mass, c - is a speed of light. Using this formula you can even count the conversion of energy to mass and vise versa.