Question

What is the atomic number (Z) of an atom containing 30 neutrons and having A= 70?

Answer 1

A= mass number = number of protons and neutrons in the nucleus

Z= number of electrons = number of protons
Given, number of neutrons= 30

Z = A - 30 = 70 - 30 = 40

Z = 40

I hope I was helpful

Answer 2

Answer: The atomic number of the given element is 40.

Explanation:

Atomic number is defined as the number of protons that are present in an atom. It is represented as Z.

Z = Atomic number = Number of protons

Mass number of the element is defined as the sum of number of protons and number of neutrons that are present in an atom. It is represented as A.

A = Mass number = Number of protons + Number of neutrons

We are given:

Number of neutrons = 40

Mass number = A = 70

Putting values in mass number equation, we get:

70 = Number of protons + 30

Number of protons = Z = 70 - 30 = 40

Hence, the atomic number of the given element is 40.