Question

In a Covalent bond, how do the atoms get eight electrons on their outer orbit?

Answer 1

8 is not a compulsion, in case of bond between two hydrogen atom there are just 2 electrons, yea 8 electrons is the criteria of octet rule for the stability of atoms but it aint compulsion

Answer 2

It is shared.

Answer 3

If an element with 7 electrons in the outer shell and another element with just one electron in the outer shell get close together they make a "bond" which contains TWO electrons; one from each element. This way, each element "feels" like it has 8 electrons on its outer shell.