Sodium (Na)
Sodium is the 11th element, a alkali metal in the s-block. Its standard atomic weight is 22.99.
Sodium
22.99
What the table records
- Atomic number
- 11
- Standard atomic weight
- 22.99
- Group
- 1
- Period
- 3
- Block
- s-block
- Category
- Alkali metal
- [Ne] 3s1
- Valence electrons
- 1
- Typical valence
- 1
- Van der Waals radius
- 2.4 Å
- Covalent radius
- 1.66 Å
Molecules containing sodium
The lightest named structures in this library that contain Na.
Sodium
Na · 22.99 g/mol
Sodium ion
Na+ · 22.99 g/mol
Sodium hydride
HNa · 24 g/mol
sodium boranuide
H₄BNa · 37.83 g/mol
Sodium Hydroxide
HNaO · 40 g/mol
sodium methanolate
CH₃NaO · 54.02 g/mol
Sodium Chloride
ClNa · 58.44 g/mol
Sodium Cyanate
CNNaO · 65.01 g/mol
sodium ethanolate
C₂H₅NaO · 68.05 g/mol
Hydrochloric acid sodium hydroxide
H₂ClNaO · 76.46 g/mol
Sodium acetate
C₂H₃NaO₂ · 82.03 g/mol
sodium hydrogen carbonate
CHNaO₃ · 84.01 g/mol
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.