Question

define atomic mass and atomic number​

Answer 1

mass of an atom of a particular chemical substance is called atomic mass

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Answer 2

Answer:

A property closely related to an atom's mass number is its atomic mass. The atomic mass of a single atom is simply its total mass and is typically expressed in atomic mass units or amu. By definition, an atom of carbon with six neutrons, carbon-12, has an atomic mass of 12 amu.