An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.



Q.42:- An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.

 

 

Answer:-



Mass number = protons+neutrons = p+n = 81 (given)
Let p be x, then neutrons = x + (31.7/100)x = 1.317 x
∴ x + 1.317 x = 81
⇒ 2.317 x = 81
⇒ x = 81/2.317 = 35
Thus, protons = 35 = atomic number.
The symbol of the element is 81Br35 or 8135Br