How do atoms form a new substance?
(a) by gaining electrons from each other
(b) by sharing electrons with each other
(c) by losing neutrons to each other
(d) by losing electrons

             Atoms combine as the electrons from each atom are attracted to the nuclei of the atoms. This results in bonds ranging from 100% covalent to bonds with high ionic character. The combination of atoms to form compounds occurs when the compounds being formed are at lower energy than the original atoms.

Abbreviated as mg-25.