Sodium
Barium is an element, with a chemical symbol of Ba. As an element it does not have a formula.
With the symbol of a chemical element - of course, if you think to a chemical formula.
Chemical symbol is code for a chemical element. Chemical formula is way of expressing information.
It is an element, its chemical symbol is F.
Each chemical element has a standardized chemical symbol, not a formula.
The chemical symbol represent a chemical element.
Fe is a chemical symbol for the element iron.
The chemical symbol (not formula) of phosphorus is P.
Germanium is an element, and as such does not have a chemical formula per se. Rather is has a chemical symbol, which is Ge.
A chemical symbol represents an element. A chemical formula represents a compund. a chemical formula is like this H2O, that is water, a chemical symbol is just this H, that is hydrogen.
Helium (He) is a chemical element, not a compound; the chemical symbol is He.
Calcium is a chemical element with the symbol Ca.