Question

An isotope of zirconium has ${\mathbf{25}}\%$ more neutrons as compared with protons. Atomic mass number of isotope is
A. $40$
B. $50$
C. $10$
D. $90$

Answer 1

in the given question atomic mass of an isotope of zirconium is asked as zirconium has five naturally occurring isotopes.This has a refractory property, is hard and resistant to chemical attack due to these properties, zircon has many applications.

Complete Step by step answer:
Zirconium is a chemical element with the symbol $Zr$ and atomic number 40. The name zirconium is given from the name of the mineral zircon which means the word is related to Persian zargun that is zircon; zar-gun, gold-like or can be called as gold.
All zirconium atoms have $40$ protons; thus, the atomic number will be $40$.
So, by the formula $A = p + n$
Where, $A$= mass number (the nucleon number),
$p$ is the number of protons,
$n$ is the number of neutrons.

The number of neutron is$\left( {x + 0.25x} \right) = 1.25x$, where $\left( {x = 1} \right)$
By putting the values in $A = p + n$we get;
${\text{A}} = 40 + 1.25 \times (40)$
So, $A = 90$
The isotope has an atomic mass number $90$, meaning that it has $90$ neutrons.

Hence the correct option is D.

Note: Zirconium compounds do not have any known biological role. zirconium has a ductile, lustrous, greyish-white color, and is a soft malleable metal that is solid at room temperature. Naturally occurring zirconium has five isotopes. Zirconium is a by-product of the processing of the titanium minerals ilmenite and rutile, mining and as well as tin mining process.