The outermost shell of an atom, the valence shell, is where the electrons are located that participate in chemical bonds. Each element has a different number of valence electrons; this number determines the number of bonds an element can form in a chemical reaction.

The outermost shell of an atom consists of electrons and contains every type of orbital: s, p, d and f. The s orbital has no number associated with it, so it is represented by a lowercase s.

The p orbital has 3 numbers associated with it, so it is represented by a capital P (example: 1s2). The d orbital has 5 numbers associated with it, so it is represented by D (example: 1s22p4). The f orbital has 7 numbers associated with it, so it is represented by F (example: 1s22s22p6).

Last modified: August 1, 2022