Answer:
Isotopes are variants of an element, where the number of neutrons is different but its number of protons stay the same.
Explanation:
If the number of protons had changed then it would just be a different element.
Electron number changing simply adds charge to the atom, and doesn't change it or anything.
PLS GIVE BRAINLIEST
The answer for this question is niche.
So what is the question about
i don't understand
Answer is all of the above. Solids have definite shapes, volumes, and mass. Liquids don't have a fixed shape, but have a fixed volume. Gases have neither a fixed shape, volume, or mass
Oxygen and selenium helium and selenium oxygen and helium carbon and oxygen