Question

What is the difference in number of neutrons in Protium and Deuterium?
A. 1
B. 2
C. 3
D. 4

Answer 1

To answer this question, you should recall the concept of isotopes. Isotopes are defined as the chemical entities of an element that differ in the number of neutrons in their nuclei. Protium, Deuterium and Tritium are the three isotopes of hydrogen.

Complete step by step answer:
Each atom is made up of subatomic particles. These are Protons, neutrons, and electrons and these essential for formation of any atom. Atoms of two different elements have different numbers of protons, neutrons, and electrons. This means that each element has a unique identity, different properties, charges and differ in mass. Also, the roles of each of the subatomic particles are quite different from each other. The difference in these subatomic particles is that they differ in charge.
Protium and deuterium have the same atomic number and different mass number, Protium is denoted as $H_1^1$ and deuterium as $H_1^2$. We can see that they have 1 proton and 1 electron each. But they have 0 and 1 neutrons respectively.
So, the difference in the number of neutrons = 1.

Hence, the correct answer to this question is option A.

Note:
Make sure you remember the difference between isotopes, isotone, isobars and isoelectronic species. Isotopes refer to the atoms of the same element having the same atomic number but different mass numbers. According to Moseley’s law, the chemical properties of an element depend on the number of electrons present and their configuration within an atom and as the isotopes have the same number of electrons it results in the fact that they exhibit similar chemical properties. Isotones refers to two nuclides which have the same number of neutrons, but different proton number. Isoelectronic species refers to the elements or ions that have an equal number of electrons. Isobars refer to the atoms of different elements with different atomic numbers but the same mass numbers. They have different chemical properties because they have different atomic numbers.