Question

what is atomic mass​

Answer 1

Explanation:

The atomic mass (ma or m) is the mass of an atom. Although the SI unit of mass is kilogram (symbol: kg), the atomic mass is often expressed in the non-SI unit dalton (symbol: Da, or u) where 1 dalton is defined as 1⁄12 of the mass of a single carbon-12 atom, at rest.[1]The protons and neutrons of the nucleus account for nearly all of the total mass of atoms, with the electrons and nuclear binding energy making minor contributions. Thus, the atomic mass measured in Da has nearly the same value as the mass number. Conversion between mass in kg and mass in Da can be done using the atomic mass constant {\displaystyle m_{\rm {u}}={{m({\rm {^{12}C}})} \over {12}}=1\ {\rm {Da}}}.

The formula used for conversion is:[2][3]

{\displaystyle 1\ {\rm {Da}}=m_{\rm {u}}={M_{\rm {u}} \over {N_{\rm {A}}}}={M(^{12}C) \over {12\ N_{\rm {A}}}}=1.66053906660(50)\cdot 10^{-27}\ {\rm {kg}}}

where {\displaystyle M_{\rm {u}}} is the molar mass constant, {\displaystyle N_{\rm {A}}} is the Avogadro constant and {\displaystyle M(^{12}C)} is the experimentally determined molar mass of carbon-12

Answer 2

Atomic mass is defined as the sum of the total number of protons and neutrons present in the nucleus of an atom. For example nitrogen has seven protons and seven neutrons,therefore its mass number is 14