Helium-6 and Helium-7 are isotopes. the nucleon number(mass number) of helium-6 is 6 and of helium-7 is 7.

(a) What is the meaning of the term isotopes?

(b) compare the number of the electron, proton, a neutron in one atom of helium-6 and one atom of helium -7

(c) Explain why helium does not react with other elements to form compounds?

Solution:

(a) Different atoms of the same element have a different number of the neutron that term refers to isotopes.

(b) i- Each atom of both atoms i-e helium-6 and helium-7 has 2 electrons.

(ii) Each atom of both atoms i-e helium-6 and helium-7 have 2 protons.

(iii) But number of neutrons differs in both atoms i.e helium -6 has 4 neutrons and helium -7 has 5 neutrons in the respective nucleus