Question

An element with mass no. 81 contains 31.7 % more neutron than proton. Assign atomic symbol

Answer 1

Mass no. = 81 ,

p + n = 81

If protons are x then neutrons = x + ( 31.7 /100 ) x = 1.317 x
x + 1.317 x = 81

or x = 35

So protons = 35 hence atomic number = 35

Symbol: ⁸¹Br₃₅