Question

Why do ' how do atoms combine?

Answer 1

atoms combine like that

Most interactions among atoms take place in the outermost shell of each atom. The number of each electron in this shell determines how an atom combines with other atoms to form compounds. When atoms combine they gain, lose or share electrons in such a way that the outer shells become chemically complete.

Answer 2

when two atoms have to complete their octet and to become stable one atom lose and other atom gains.

then two atoms are combine