Question

Define atomic Mass unit . State how do atoms exist .

Answer 1

A unit of mass equal to 1/12 the mass of an atom of the most common isotope of carbon ,carbon 12, which is assigned a mass of 12. A hydrogen atom has a mass of 1 atomic mass unit since its mass is 1/12 the mass of carbon 12.

Answer 2

a unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.Atoms of most of the elements exist in the form of molecule or ion, since they are most reactive. For example, hydrogen, oxygen, chlorine, etc. However, atoms of some elements, which are non-reactive, exist in free-state in nature. For example helium, neon, argon, etc