(a) Define atomic mass unit. What is its symbol ?
(b) Define atomic mass of an element.
(c) What is meant by saying that 'the atomic mass of oxygen is 16' ?
a)
An atomic mass unit (symbolized AMU or amu) is defined as precisely \({1/12 the mass of an atom of C12 The C12 atom has six protons and six neutrons in its nucleus. In imprecise terms, one AMU is the average of the proton rest mass and the neutron rest mass.
b)Atomic mass
The atomic mass of an element is the mass of one atom of that element in atomic mass units or (u)
c)Atomic mass of an element is the relative mass of its atom as compared with the mass of a C12 atom taken as 12 units.Hence, atomic mass of O2 is 16 u means that one atom of oxygen is 16 times heavier than 112 of a C12.
Atomic mass of oxygen is 16 means that mass of an oxygen atom is 16 u.