How are covalent bonds formed?

1 Answer
Oct 3, 2016

By sharing electrons.

Explanation:

The simplest, hydrogen, has only one electron, but all atoms "want" their outer shell to be filled.
Now by sharing their electrons, in a way two #H# atoms both have two electrons: This is denoted by:

#H:H# or more usually

#H-H# where #-# stands for an electron- pair .

Oxygen, that lacks two electrons to make a full (8) shell looks like:

#O::O# or, more usually #O=O# (a double bond)

Different atoms can also share electrons like:

#H-O-H# (water) or #O=C=O# (carbondioxide)