Atomic number and the mass defect of nucleon binding is always small compared to the nucleon mass, the atomic mass of any atom, when expressed in unified atomic mass units (making a quantity called the "relative isotopic mass"), is within 1% of the whole number "A". Atoms with the same atomic number "Z" but different neutron numbers "N", and hence different atomic masses, are known as isotopes. A little more than three-quarters of naturally occurring elements exist as a mixture of isotopes (see monoisotopic elements), and the average isotopic mass of an isotopic mixture for an element (called the relative atomic mass)
Given name a name is not assigned at birth, one may be given at a naming ceremony, with family and friends in attendance. In most jurisdictions, a child's name at birth is a matter of public record, inscribed on a birth certificate, or its equivalent. In western cultures, people normally retain the same given name throughout their lives. However, in some cases these names may be changed by following legal processes or by repute. People may also change their names when immigrating from one country to another with different naming conventions. In certain jurisdictions, a government-appointed registrar of births may refuse to