Question

What is the heaviest element?

Answer 1

Hint: Elements arranged in the modern periodic table are placed in an ascending order of their atomic numbers which follows almost the same order as that of atomic mass. Hence the elements belonging to high groups and periods tend to be the heaviest.

Complete answer:
An atom possesses mass by the virtue of the protons and neutrons present inside its nucleus known as nuclear particles. An increase in the number of protons and neutrons is accompanied by a corresponding increase in the atomic masses as well as atomic weights. Thus it is valid to assume that the element having the maximum number of nuclear particles is the heaviest element yet we see contradictory results.
An increasing number of nuclear particles in an element is also encountered by decreasing stability of the atomic nucleus. Heavier elements tend to show a radioactive decay or natural fission reactions (without getting triggered by a neutron) in which the unstable nucleus splits into two lighter nuclei with an increase in the overall stability.
Thus the heaviest element can be decided by keeping in mind the following two factors:
1.Higher atomic weight
2.Stable enough to not show a natural fission reaction.
The element in the periodic table that fits the above two criteria is Uranium. Hence Uranium is the heaviest stable element known to humankind.

Note:
Many scientists debate about Uranium being the heaviest or not as there have been many discoveries with heavier elements. But a common issue in all these elements is that they have a lifetime of a few seconds and cease to exist for longer periods of time.