Question

Monazite is a source of:
(a) He
(b) Kr
(c) Ar
(d) Ne

Answer 1

Hint: Monazite is a mineral ore from which the rare-earth elements are obtained and from above mention all the elements, the element which is having the mass number as 4 and atomic number as 2. Now you can easily identify that element.

Complete answer:
First of all, let’s discuss what is monazite. Monazite is a mineral which is somewhat reddish- brownish in colour and is an important mineral ore for the earth elements which are not commonly found i.e. for the rare earth elements.
Monazite ore is found in India, Madagascar and in South-Africa.
The rare earth elements which are obtained from the monazite ore are thorium (Th), lanthanum(La), cerium(Ce), neodymium( Nd), helium (He) and some others. Out of all these elements, cerium is present in large amounts.
Now, considering the statement;
From the above, all the noble gases, helium is the only element which is obtained from the monazite ore.
Helium is a p-block element and lies in the 18th group and 1st period of the periodic table and comes under the category of noble gases and has the atomic number as 2 and mass number as 4. It has two electrons present in its valence shell and has fully stable electronic configuration.
Hence, from the above, it is clear that monazite is the source of helium.

So, option (a) is correct.

Note: Helium gas along with hydrogen gas is used in the balloons , as an inert gas for welding purposes, in NMR spectrometers and it is also used as a coolant to cool the liquid hydrogen and oxygen and is also used in the industries.