Video Transcript
How many electrons are shared in a
single bond between two hydrogen atoms?
Hydrogen is a nonmetal. When two nonmetal atoms share one
or more pairs of electrons, a covalent bond is formed. Hydrogen atoms have one negatively
charged electron that is tightly bound to the hydrogen nucleus, which contains one
positively charged proton. This electron is hydrogen’s only
valence electron, which are the electrons found in the outermost electron shell, or
valence shell. The valence shell of hydrogen has
space for two electrons, but only one space is occupied.
When two hydrogen atoms are near
one another, a combination of attractive and repulsive electrostatic forces exist
between the two atoms. There is electrostatic repulsion
between the electrons of the two atoms and the protons of the two atoms. But there is also electrostatic
attraction between the valence electron of one hydrogen atom and the proton of
another hydrogen atom.
As the forces balance out, the most
stable energetic arrangement emerges. In this arrangement, the two
electrons from the two hydrogen atoms are equally shared between the two atoms. We can see that by sharing
electrons, each of the hydrogen atoms now has two electrons in its valence
shell. As this valance shell can only hold
two electrons, the valence shell of each atom is now full.
We know that when two nonmetal
atoms share one or more pairs of electrons, a covalent bond is formed. More specifically, when a single
pair of electrons is shared between two atoms, a single covalent bond is formed.
From our discussion, we can see
that the number of electrons shared in a single bond between two hydrogen atoms is
two.
