How do you write the noble-gas electron configuration for boron?

1 Answer
Oct 1, 2016

The noble gas configuration is #["He"]"2s"^2"2p"^1"#.


Boron has atomic number 5, which means that it has 5 protons in its atomic nuclei. A neutral atom has the same number of electrons as protons, so a neutral boron atom has 5 electrons.

When writing a noble gas shorthand electron configuration, you start with the noble gas in the previous period, then continue with the electron configuration of the elements in the new period. The symbol for the noble gas is enclosed in brackets. Then the next period's electron configurations are added.

In the case of boron, it is in period 2 on the periodic table, so the noble gas will be helium, #["He"]#, which is the noble gas in period 1. Because boron is in group 13, its electron configuration will end with 2s and 2p sublevels. Therefore, the noble gas electron configuration of boron would be #["He"]"2s"^2"2p"^1"#.