Question

Name the element that does not contain any neutron in it:
A.Helium
B.\[L{i^{2 + }}\]
C.Proton
D.Hydrogen

Answer 1

Hint:
Atoms are made up of subatomic particles, protons, neutrons and electrons. In a neutral atom the number of protons are equal to the number of electrons to maintain the electrical neutrality. The mass number is the sum of the number of protons and number of neutrons.

Step-by-step explanation:
Step 1:
Hydrogen, the first element in the periodic table is the lightest element known.
Step 2:
Hydrogen has three isotopes, protium \[_1^1P\] which has one mass number and one atomic number, deuterium \[_1^2D\] which has mass number two and atomic number one and tritium \[_1^3T\] where the mass number is three and atomic number is one.
Step 3:
So, Protium having one mass number has only one proton, one electron and do not have a neutron, whereas an atom of Deuterium has one proton, one neutron and one electron and an atom of Tritium has one proton, two neutrons and one electron.
Step 4:
An atom of Helium \[_2^4He\] has two protons, two neutrons and two electrons.
An ion of \[L{i^{ + 2}}\] contains three protons, four neutrons and one electron.
A proton is represented by \[{H^ + }\]. It has only one proton, no neutron and no electron.
Though it may seem that it is protium and isotope of hydrogen which has no electrons but it is not mentioned in the given question. On the contrary a proton is a mono positive hydrogen ion which is confirmed of not having any neutrons present in it.
Hence the correct answer is (C) which is proton.

Note: Students may get confused between protons and hydrogen but we have to consider all the isotopes present in hydrogen when we consider hydrogen as a whole.