Sodium (na) has 11 protons and 12 neutrons. which of the following is the most likely atomic weight of sodium?
22.98
12.98
11.98
24.98

22.98 is the most likely atomic weight of sodium

Explanation:

Sodium is a mono-isotopic element and its atomic weight is determined solely by its isotope.Usually Atomic masses are not integers since they are taken as the average weight of  the atomic mass of the  isotope of the element that are occuring  naturally. atomic weight of the atom depends on the 'atomic mass unit' (amu), that  is 1/12th of  the mass of carbon-12 present in its ground state.  Electrons  also contribute to the atomic mass.