GENERAL KNOWLEDGE

Detailed explanation-1: -An element’s or isotope’s atomic number tells how many protons are in its atoms. An element’s or isotope’s mass number tells how many protons and neutrons in its atoms.

Detailed explanation-2: -The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom. Consider the table below, which shows data from the first six elements of the periodic table. Consider the element helium. Its atomic number is 2, so it has two protons in its nucleus.

Detailed explanation-3: -Together, the number of protons and the number of neutrons determine an element’s mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.

Detailed explanation-4: -Atomic mass is equal to the sum of the number proton and number neutron.

Detailed explanation-5: -The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.