an element with mass number 181 contains 32% more neutrons as compared to protons. What is the symbol of that element ?

Options

A. Pt
B. Pd
C. Au
D. Hg

Answer

A

Explanation

As we know that, mass number of the element (A) = no of protons +number of neutrons
= 181 (given) . . . (i)
Let the number of protons = a
Then , according to the given condition, the
number of neutrons a + 0 . 3 2a = 1.32a
Hence, from Eq. (i),
a + 1.32a = 1.81
2 .3 2a = 181
` a = 78 .02 ~~ 78 `
Thus, the number of protons = 78
Element having 78 protons is platinum (Pt) .