Question

In the nucleus of 20ca40, there are

a. 20 protons and 40 neutrons

b. 20 protons and 20 neutrons

c. 20 protons and 40 electrons

d. 40 protons and 20 electrons

Answer 1

Answer:

In nucleus of ⁴⁰₂₀Ca ,  there are 20 protons and 20 neutrons. Option b.

Explanation:

Protons and neutrons are found in the nucleus of an atom and collectively known as nucleons. Protons and neutrons are the factors used to determine the Atomic mass and mass number of an atom.

Atomic mass on the other hand is the number of protons in the nucleus. It is the number used to identify elements in the periodic table. In this case the atomic number of calcium is 20, meaning there are 20 protons in the nucleus of this calcium.

Mass number, also known as the nucleon number, is the total number of protons and neutrons in an atom. Since the number of protons are 20, we subtract the number of protons from the mass number to find the number of neutrons. Mass number of 40 - 20 Protons = 20 Neutrons. The number of neutrons are 20.

Therefore the correct option is, Option b. 20 protons and 20 neutrons.

Points to note:

1) The number of electrons in an atom is equal to the number of protons in the atom. Hence in this case we have 20 electrons as well.

2)The atomic mass of an element remains constant in all the isotopes of the same element.

3)) The mass number of an element can vary in the isotopes of the same element( The difference between the isotopes of the same element, is in the mass number).

                      Summary:

• Mass number = Protons + Neutrons
• Atomic mass = Number of protons
• Number of protons = Number of electrons