I think it’s “number” and “type”
Answer to this is Radioactive isotopes.
Isotopes are the species of the same element having different atomic masses that means the number of protons remains the same but number of neutrons do differ. For example
and
are the two isotopes of Hydrogen (
).
Radioactive isotopes are the isotopes which release some kind of energy in the form of alpha particles, beta particles or gamma radiation. Examples of each of the decay processes are :
Alpha Decay: In this decay one alpha particle having atomic mass 4 and atomic number 2 or we can say a He molecule will come out. 
Beta Decay: In this decay a
particle is emitted increasing the atomic number of the reactant by 1 unit.

Gamma Radiation: In this type of reaction only radiation is emitted out which does not change the original molecule.

Ethanol is: flammable, liquid at room temperature, the boiling point is 78.37 ° C.
It’s wave motion. Because when wave passes throug an object, some of the other material can go though on other object(s).
Answer: Lithium
Explanation:
The ratio for the reaction of Li and water is the same, but there are more moles of water than lithium. Therefore, lithium is the limiting reactant.