Question

Define Atomic number,Atomic mass ,Mass number ​

Answer 1

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☛ Atomic number:-This number shows the position of an element in the periodic table .The number of protons present in the nucleus or the number of electrons present outside the nucleus of an atom of an element is known as atomic number.It is denoted by Z .

☛ Atomic mass :- The atomic mass of an element is a number which express as to how many times an atom of the element is havier than 1/12th of the mass of carbon atom (C¹²).

Atomic mass = Mass of an atom of element / 1/12 mass of a carbon atom (C¹²).

☛ Mass number :- The sum of neutrons and protons present in the nucleus of an atom is called mass number.It is denoted by A.

Mass number = No.of Neutrons + No.of Protons

or,

A = n + p

let's know about atom

☛ Atom :- An atom is the smallest part of an element in which all the properties of the matter remains alike and which participates in a chemical reaction.It is not capable of independent existence.

• The size of an atom is very small and the mass is even less.

• Hydrogen atom is the smallest and lightest.

• Its radius is around$\sf\:0.3\times\:{10}^{-10}\:cm$

Answer 2

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Atomic number and mass number are always whole numbers because they are obtained by counting whole objects (protons, neutrons, and electrons). The sum of the mass number and the atomic number for an atom (A-Z) corresponds to the total number of subatomic particles present in the atom. The mass number reports the mass of the atom’s nucleus in atomic mass units (amu).