Question

identify the element x in the geometrical representation 20x40​

Answer 1

Explanation:

Atomic number =15= No. of electrons= No. of protons

Mass Number = 31

Number of neutrons + number of protons= Atomic mass number.

∴ Number of neutrons =31−number of protons

=31−15

=16

Hence, option C is

Answer 2

Answer:

The element X is Calcium.

Explanation:

The element X is Calcium.

The representation of the element X is as follows- $20X_4_0$

Hence the atomic number of X is 20 and the mass number of X is 40.

Hence element X is calcium.

The symbol of Calcium is Ca and it has an atomic number of 20.

Ca is an alkaline earth metal residing in group 2 of the modern periodic table.