Question

What is the most unstable element?

Answer 1

Hint: The stability of the element depends upon the outer shell configuration of the element. The elements whose outer shell configuration is either full-filled or half-filled are more stable as compared to other elements.

Complete Step by Step Solution:
An atom is considered to be stable when it does not have any charge or it is electrically neutral. The atomic number of stable elements is usually less than 82. There are various factors that affect the stability of the elements such as the number of electrons, and protons, and whether there is a presence of any charge or not.

Francium is considered to be the most unstable element that is present. It occurs naturally. The longest-lived isotope of francium is francium-223 which has a half-life of 22 minutes only. However, there is a presence of other chemical elements that have a half-life that is less than that of francium.

Francium was discovered by Marguerite Perey of Curie Institute, France. It is denoted by Fr.
Francium is an extremely radioactive element and is known to have no biological uses and is only used for research purposes. It is a very rarely occurring element that has the tendency to decay very quickly.

It is a possibility that francium may occur as a liquid and not a solid at room temperature.

Note: The boiling point of francium is \[{677^0}C\] and its melting point is \[{27^0}C\]and has the valency 1. It is the second least electronegative element and it also shows the properties similar to caesium.