Video Transcript
What is the maximum number of
electrons in the first electron shell?
An electron shell is a place around
the nucleus where an electron could be. The first electron shell is simply
the electron shell that is closest to the nucleus. The first electron shell is very
small, so it can only fit two electrons. There aren’t very many ways of
simply remembering this, but you can nudge your memory by looking at the periodic
table.
There are only two elements in the
first period, the first row, of the periodic table. A hydrogen atom has one electron,
and a helium atom contains two. When we go to lithium, we have to
go down a row, and we have three electrons per atom. And the third electron has to go in
the second shell because the first is full. When we move down a row in the
first few rows of the periodic table, it means we’re adding the outer electrons to a
new shell. So, that’s how we can remember that
the maximum number of electrons in the first electron shell is two.
