This photograph shows a hydrogen fuel cell powered tram. The tram, which uses hydrogen as a source of energy, was developed as a part of the effort to reduce China's greenhouse gas emissions.
Hydrogen is the chemical element with the chemical symbol H. But did you know that there are different forms of hydrogen?
The three naturally occurring forms of hydrogen are called protium, deuterium, and tritium. They can be written as hydrogen-1, hydrogen-2, and hydrogen-3. In this lesson, you will learn what the numbers “1,” “2,” and “3” stand for, and how those numbers relate to protons and neutrons.
Question
Recall that the atoms of a given element always have the same number of protons. There is one proton in the nucleus of every hydrogen atom. What does this tell us about the atomic number of hydrogen?
The number of protons in an atom is referred to as the element's atomic number. Since an atom of hydrogen has 1 proton in its nucleus, hydrogen has an atomic number of 1.
