Which statement is true about the atomic mass?
a. it can be greater than the atomic number
b. it is never greater than the atomic number
c. it always equals the atomic number
d. it is always lower than the atomic number

The statement that is true about the atomic mass is

Further explanation:

The smallest particle that is the building block of matter is known as an atom. Most of the space in an atom is empty and its mass is concentrated inside a small region called the nucleus.

Protons, electrons, and neutrons are the three subatomic particles that are present in the atom. Electrons revolve around the nucleus in definite orbits.

An atom is also written as , where A is the atomic mass or mass number, Z is the atomic number and X is the letter symbol of the element.

Atomic number is equal to the number of protons present in the nucleus of the atom. Atomic mass is the total number of nucleons (protons and neutrons) within the atomic nucleus. It is also known as the mass number.

Atomic mass is the sum of the number of protons and the number of neutrons present in the nucleus of an atom. But the atomic number is equal to the number of protons only. So atomic mass is greater than that of atomic number. For example, sodium is written as . Its atomic number is 6 whereas its atomic mass is 12 which is greater than 6. Therefore statement A is correct, whereas the remaining are incorrect.

Learn more:

1. Component of John Dalton’s atomic theory: link

2. Basis of investigation for the scientists: link

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Atomic structure

Keywords: electron, proton, neutron, atom, atomic mass, mass number, atomic number, A, X, Z, letter symbol, nucleons, correct, incorrect, 6, 12, C, greater.