Question

an element X has mass number 4 and atomic number to write the valency of this element will it react with other atoms of different elements?​

Answer 1

$\huge\mathfrak\red{ANSWER}$

✍We know that only valence electrons take part in bond formation with different atoms in the atom of x element there are only two electrons since atomic number is 2 thus K shell is fully filled for this item hence its valency is zero it will not react with other atoms of different elements.

Answer 2

ATOMIC NUMBER = 4

ELECTRON CONFIGURATION = 2,2

NUMBER OF VALENCE ELECTRON = VALENCY

SO, IT'S VALENCY IS 2

HENCE IT HAS STABLE ELECTRONIC CONFIGURATION SO IT DOESNOT REACT WITH OTHER ELEMENTS.

IT IS A NOBLE GAS.