Answer:
Hydrogen is an element
Explanation:
Hydrogen is an element with only hydrogen atoms, whereas air, carbon dioxide, and water are all made up of multiple elements with different types of atoms.
Answer:
There are multiple ways to check mass but I'll tell you one. Look below
Explanation:
One easy way of checking atomic mass is by adding protons and neutrons.
For example:
We have 5 protons and 4 neutrons.
5+4=9
I hope this helps (: