The $IUPAC$ name of an element with atomic number $119$ is $.........$

Atomic numbers of three elements $E_1$,$E_2$ and $E_3$ of the periodic table are $Z_1$,$50$ and $Z_2$ respectively. From the position of the elements shown in the figure,the value of $(Z_2 - Z_1)$ is:

In which of the following groups would placing Helium satisfy all its properties?

An element has $[Ar] 3d^1$ configuration in its $+2$ oxidation state. Its position in the periodic table is

According to the modern periodic law of elements,the variation in properties of elements is related to their

The number of elements present in the fourth period is