# What is the shorthand electron configuration for As?

The configuration may be written as: $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 3 {d}^{10} 4 {s}^{2} 4 {p}^{3}$
Each whole number refers to the energy shell in which the electrons are located. The letters $s , p , d , f$ refer to orbitals within each energy shell where electrons are very likely to be located. Each orbital can hold up to a maximum number of electrons ( the $s$ orbital 2, the $p$ orbital 6 ... and so on). If you add up the number of electrons ( 33 in this case) the total equals the number of protons in the nucleus, and is also the atomic number for that element.