NCERT Question 13 - Chapter 4 Class 9 - Structure of Atom

Last updated at April 16, 2024 by

Composition of the nuclei of two atomic species X and Y are given as under

                  X  Y

Protons   = 6  6

Neutrons = 6  8

Give the mass numbers of X and Y. What is the relation between the two species?

 

Answer

 

X

Y

Protons

6

6

Neutrons

6

8

Mass number of an atom = Number of protons + Number of Neutrons

6 + 6 = 12

6 + 8 = 14



  • Protons of X = Protons of Y
  • So, Atomic number  of X = Atomic number of Y
  • Mass number  of X ≠ Mass number of Y

 

Elements having the same atomic numbers but different mass numbers are called isotopes and have the same electronic configuration and chemical properties.

Therefore, X and Y are isotopes.

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