Question

the isotope of an atom containing 40 protons and 51 neutrons suddenly has two neutrons added to it. what isotope is created?
zirconium-93
zirconium-53
antimony-53
antimony-93

Explanation:

Step1: Identify element by proton number

The number of protons determines the element. The element with 40 protons is zirconium (Zr).

Step2: Calculate new mass - number

The original number of neutrons is 51, and 2 neutrons are added, so the new number of neutrons is $51 + 2=53$. The mass - number is the sum of protons and neutrons. So the mass - number is $40+53 = 93$.

Answer:

Zirconium-93