Nonmetals

NONMETALS

Elements	Latin names	Symbol	Atomic number	Atomic weight	Electronic configuration	Valency = number of valence electrons or (8-number of valence electrons)
Nitrogen	Nitrogenium	N	7	14.0067	2, 5	8 - 5 = 3
Phosphorous	Phosphorous	P	15	30.973	2, 8, 5	8 - 5 = 3
Oxygen	Oxygenium	O	8	15.994	2, 6	8 - 6 = 2
Sulphur	Sulphur	S	16	32.065	2, 8, 6	8 - 6 = 2
Fluorine	Fluorum	F	9	18.99	2, 7	8 - 7 = 1
Chlorine	Chlorum	Cl	17	35.45	2, 8, 7	8 - 7 = 1
Bromine	Bromum	Br	35	79.904	2, 8, 18, 7	8 - 7 = 1
Iodine	Iodum	I	53	126.904	2, 8, 18, 18, 7	8 - 7 = 1

Orbital diagram of atoms of some of the Nonmetals:

The atoms of Noble gases have stable (ns², np⁶) configuration, there octet is complete therefore they do not combine.
Atoms of other elements combine in order to complete their respective octet (attain 8 electrons in the valence shell).
They try to complete their octet either by gaining /losing /sharing electrons.
They form cations by losing electrons and anions by gaining electrons.