Explanation:
atomic mass
Really...i think it can also be atomic number..
Answer::Democritus
Explanation
The idea that all matter is made up of tiny, indivisible particles, or atoms, is believed to have originated with the Greek philosopher Leucippus of Miletus and his student Democritus of Abdera in the 5th century B.C. (The word atom comes from the Greek word atomos, which means “indivisible.”) These thinkers held that,
Largest to smallest: barium, calcium, selenium, oxygen
Answer:
The mass number tells us the number (the sum of nucleons) of protons and neutrons in the nucleus of an atom. The atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. It is traditionally represented by the symbol z
Explanation:
