EVERYDAY SCIENCE

Detailed explanation-1: -The mass of an atom is the sum of number of protons and number of neutrons present in that atom in atomic mass unit . The total number of protons and neutrons present in a nucleus is termed as nucleon . Therefore, the mass of an atom is equal to the number of nucleons in atomic mass unit .

Detailed explanation-2: -The mass number of an atom is equal to the number of protons plus the number of neutrons that it contains. In other words, the number of neutrons in any atom is its mass number minus its atomic number. Although all atoms of a given element must have the same atomic number, they need not all have the same mass number.

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: -The number of protons in a nucleus is called the atomic number and always equals the number of electrons in orbit about that nucleus (in a nonionized atom).

Detailed explanation-5: -Atomic number = Number of protons.