GENERAL KNOWLEDGE

Detailed explanation-1: -Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element.

Detailed explanation-2: -One item on most periodic tables is the atomic mass of each element. For many applications, only one or two decimal places are necessary for the atomic mass.

Detailed explanation-3: -Answer and Explanation: Many of the atomic masses listed on the periodic table are decimal values because it’s the weighted average mass of all of the isotopes of that element. The mass of each isotope of an element is multiplied by its percent abundance in nature.

Detailed explanation-4: -Solution : The total number of protons and neutrons in the nucleus of the atom is called the atomic mass number (A). The number of electrons or protons in an atom is called the atomic number (Z). Both protons and neutrons are whole numbers, therefore, atomic numbers and atomic mass numbers are always in whole numbers.