Stars are made of what?

Answer 1

Stars are made mostly of hydrogen and helium in the plasma state. Traces of heavier elements can also be found.

When stars form, they are composed of approximately 70% hydrogen and 28% helium, the remaining fraction is heavier elements (metallicity). [See Link] Typically the portion of heavy elements is measured in terms of the iron content of the stellar atmosphere, as iron is a common element and its absorption lines are relatively easy to measure.

Answer 2

Predominantly hydrogen, same material as the primordial universe. Hydrogen and helium, and trace amounts of lithium.

Second generation stars incorporate a lot of other matter. Big stars burn through nuclear fusion, converting hydrogen into heavier elements, all the way down to iron. The rest of the period table is created through cataclysmic supernova, smashing nuclei into heavy isotopes.