ATOMIC NUMBER AND MASS NUMBER

ATOMIC NUMBER :

The number of Protons present in the nucleus of an atom is known as its ATOMIC NUMBER.

• It is generally denoted by the letter 'Z'
• This was proposed by Moseley based on X-ray spectral studies.

v^1/2 = a(Z-b)

where,

v = frequency of X-ray of element

z = atomic number of the element a and b are constants

atomic number of an element can be written as:

• Number of protons present in the nucleus of the atom
• Number of electrons present in the neutral atom of the element
• Positive charge of the nucleus of the atom
• Serial number of the element in the periodic table

Atomic number(Z) = number of protons = number of electrons

MASS NUMBER :

The sum of the number of Protons and neutrons present in the nucleus of an atom is known as its MASS NUMBER.

• It is generally denoted by the letter 'A'
• Mass number of an element is a whole number never a fractional value.
• Atomic mass of an element corrected to the nearest whole number will be the mass number of the element

Mass number(A) = Atomic number(Z) + Number of neutrons

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Now lets calculate 'A' and 'Z' of element

Enter the name of any element from Hydrogen to calcium ENTER ELEMENT NAME:

Calculate

Atomic number :
Mass number :