Question

An atom of an element contains 20 protons and 21 neutrons. Which of these is true of the element?

it is a noble gas

it is a transition element

it is a nonmetal

it is an alkaline earth metal

Answer 1

It is an Alkaline earth metal

Step-by-step explanation:

20 protons meaning the element is 20 on the periodic table-Calcium.

The number of neutrons does not matter

Calcium is not a noble gas, transition metal, and nonmetal.

Calcium is in the 2nd group meaning it is an alkaline earth metal.