Question

An element has mass number of 81. It contains 31.7% more neutrons than protons. Find the number of electrons, protons and neutrons in the element

Answer 1

Answer

Protons=25.67

Electrons=25.67

Neutrons=55.323

Explanation:

Answer 2

Answer:

We know that mass number of the element,

A = p+n = 81

Let the number of protons, p = x

Then, number of neutrons,

n= x+ 31.7 / 100x = 1.317 x

(As number of neutrons are 31.7% more than the protons.) Hence, from Eq. (i)

x + 1.317 x = 81

x = 81 / 2.317 = 34.958 = 35 (approx)

Therefore, number of protons = 35 and the symbol is ${}_{35}^{81}Br$ (Number of protons = Atomic number)

Explanation: