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Nitrogen (N)

Nitrogen is the 7th element, a reactive nonmetal in the p-block. Its standard atomic weight is 14.007.

Period 2Group 15p-blockReactive nonmetal
7N

Nitrogen

14.007

What the table records

Atomic number
7
Standard atomic weight
14.007
Group
15
Period
2
Block
p-block
Category
Reactive nonmetal
Electron configuration
[He] 2s2 2p3
Valence electrons
5
Typical valence
3
Van der Waals radius
1.6 Å
Covalent radius
0.71 Å

The configuration above is the aufbau order.

How to read these numbers

The standard atomic weight is an average over the isotopes as they occur naturally, which is why it is rarely a whole number. It is the figure a molar mass calculation uses. Work in mass spectrometry wants the monoisotopic mass of a single isotope instead, which is a different number.

The two radii are not the same measurement. The covalent radius is half the distance between two bonded atoms of the element; the van der Waals radius is how close a non-bonded atom gets before repulsion takes over, and is always the larger. Space-filling models are drawn with the second, ball-and-stick models with the first — which is why the same molecule looks so different in the two.