Question

. An atom having mass number as 40 and there are 20 neutrons present in the

nucleus. What will be the atomic number for that atom?​

Answer 1

Answer:

Atomic number is 20

Explanation:

If an atom has atomic mass 40 and no. of neutrons is 20

We know that atomic mass= no. of protons\electrons + no. of neutrons

So, 40=no. of protons / electrons +20

Now,no. of protons and electrons = 20

and, atomic number=no. of protons and electrons

Hence, Atomic number=20

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Answer 2

Required Answer :-

• The atomic number of the atom is 20.

Step-by-step explanation:

To Find :-

• The atomic number of the atom.

Solution:

Given that,

• The mass number of atom = 40
• Number of neutrons of atom = 20

∴ The proton of the atom is :-

We know that,

• No. of protons + No. of neutrons = Mass number

⟶ No. of protons + No. of neutrons = Mass number

⟶ No. of protons + 20 = 40

⟶ No. of protons = 40 - 20

⟶ No. of protons = 20.

According the question,

• The atomic number is :-

We know that,

• No. of protons = No. of electrons = Atomic number

⟶ Atomic number = No. of protons

⟶ Atomic number = 20.

∴ The atomic number of the atom is 20.