Question

What is the name of the smallest atom?

Answer 1

Hint : We now know that atoms are made up of three particles: protons, neutrons and electrons which are composed of even smaller particles, such as quarks. The name of the smallest atom is helium. Helium is a chemical element with the symbol He and atomic number $2$ .

Complete Step By Step Answer:
Helium is the smallest atom. An electron gets added to each element from left to right and in the same shell. More the attraction, less the space. Therefore helium has the smallest atomic size.
It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements. Helium is the second lightest and second most abundant element. It is present at about $24\%$ of the total elemental mass, which is more than $12$ times the mass of all the heavier elements combined.
The abundance of helium is similar to this in both the Sun and in Jupiter. This is due to the very high nuclear binding energy of helium, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay.

Note :
Helium is very unreactive. It turns out the single biggest use of helium is to support our medical imaging industry, specifically magnetic resonance imaging or MRI, and high-end material analytics that take advantage of very high magnetic fields to make the nuclear magnetic resonance, or NMR, spectroscopy measurements.