What element has a mass number of 40 and 20 protons?

An element's atomic number may be used to determine how many protons and electrons are present in that particular element. The number of neutrons in the given element may be determined from the mass number and the number of protons.

The quiz asks you to identify the element that has 20 protons and a mass number of 40.
-A specified element has a mass number of 40 and 20 protons, according to the query.
 We are aware that mass number equals the sum of the protons and neutrons.
40 mass number
Number of protons is 20, hence there are 20 neutrons after subtracting the 20 protons.
Since the element has 20 protons, it follows that it also has 20 electrons.
The fact that an element possesses 20 electrons indicates that it has an atomic number of 20.

Consequently, the element has an atomic number of 20.
 Calcium is the element on the periodic table with 20 electrons.
Consequently, calcium is the element with a mass number of 40, 20 protons, and 20 electrons.

Hence, option A is correct.