What is the total number of electrons in the valence shell of an atom of aluminum in the ground state?

1 Answer
Jun 6, 2017



Aluminium atomic number 13 has 13 total electrons the electronic configuration is

# 1s^2 2s^2 2p^6 3s^2 3p^1#

The first two electrons fill the first shell. Another eight electrons fill the second shell. This is a total of ten electrons in filled shells. That leaves 3 electrons in the third shell. This is the valance shell since it is not filled. So the #3s^2 3p^1# electrons are the valance electrons for a total of 3 valance electrons.