If you want to know where the data comes from for any particular property, then select that property. You'll see graphs for the properties as well. Values for abundances are difficult to determine with much certainty, so all values should be treated with some caution, especially so for the less common elements. Here are a few comments about the biological role of sodium.
Sodium is a vital element.
The human diet must contain a sensible amount of sodium. The importance of sodium as salt in the diet was recognized well before sodium itself was understood to be an element. This recognition formed the basis of trading of salt deposits lining the Dead Sea in biblical times by the Romans. Sorry, your Browser does not support JavaScript and so you will not be able to use this calculator. Just enter your weight in either kilograms or pounds.