Question

why do noble gas placed in a separate group​

Answer 1

Nobel gases are placed in a separate group because they are extremely unreactive & they generally do not combine with other elements of the periodic table except Xe.

Answer 2

$\Huge\tt\blue{Question}$

why do noble gas placed in a separate group

$\Huge\tt\pink{Answer}$

Nobel gases are placed in a separate group because they are extremely unreactive & they generally do not combine with other elements of the periodic table except Xe.