ICSE Class 10 Answered
(a) Mass number = number of protons + number of neutrons and atomic number = number of protons.
Therefore, number of neutrons = mass number - atomic number = 15 - 7 = 8.
(b) Element X can be written as .
(c) (i) After the loss of 1 proton, the mass number and atomic number of the nucleus will decrease by 1. The new nucleus will be (say). The change can be written as :
(ii) After the loss of one -particle, the mass number will remain the same but the atomic number will increase by 1. The element changes to (say) as follows :
(iii) After the loss of one -particle, the mass number decreases by 4 and the atomic number decreases by 2. The element changes to (say) as follows :