Hi, this is Dr. B. Let's do the Lewis structure
for BeH2.
On the periodic table, Beryllium has 2 valence
electrons and Hydrogen has 1, but we have
2 Hydrogens, so we have a total of 4 valence
electrons.
Put Beryllium here, and Hydrogen will go on
the outside.
So we've got 4 valence electrons.
We'll put 2 between atoms to form chemical
bonds: 2, 4.
Actually, we've used all our valence electrons
at this point.
Let's check and see if we have full outer
shells.
Hydrogen only needs 2, so both of those Hydrogens
are fine.
Beryllium has 4, but Beryllium is an exception:
it doesn't necessarily need 8 valence electrons.
So with that, we've done the Lewis structure
for BeH2.
This is Dr. B., and thanks for watching.
