the number is the mass number
the mass number is the number of nucleons (total number of protons and neautrons in the nucleus) so in hydrogen-3 there are 3 nucleons and as hydrogen has 1 proton, there are 2 neutrons
carbon 12 has 12 nucleons (6 protons and 6 neutrons) and carbn 13 has 13 nucleons (6 protons and 7 neutrons)
This is classified as a "Formation Reaction"
Actually the answe is mass.
Mg is a metal. Under ordinary conditions it will not form a diatomic molecule. The other 3 are non metals. They come from the right side of the periodic table and they willl form diatomic molecules.
Answer:
79.89%
Explanation:
Copper has a molar mass of 63.55
Oxygen has a molar mass of 16.00
If you add these you get 79.55
To get the mass percent of copper divide copper by the whole. 63.55/79.55*100= 79.89%