Oxygen, which is one of the chemical elements, is necessary for us to breathe.

Fluorine is one of the chemical elements, and its symbol is F.

He ate one apple.

Hydrogen is the most abundant element in the universe.

He is majoring in chemistry at university.

What does this symbol mean?

My younger sister is attending F Rank University.

He is an expert in chemistry.

This is my first question.

An isotope refers to elements with the same atomic number but different numbers of neutrons.