Answer:
6. The number of protons of the atoms
7.The atomic number is equal to the number of protons and in a neutral atom the number of electrons
8. The atomic mass of elements equals number of protons plus number of neutrons
9. Protons and neutrons
10. Electrons
11. 8+9=17
12. 20+21=41
13. 10
Explanation:
It is d, a substance that participates in a chemical reaction. You can also tell it just by looking at the stem of the term :)