Question

An element has 20 electrons and mass number 40. Write:
(a)the number of neutrons and (b) its atomic number​

Answer 1

Answer:

The element has 20 electrons.

(a) We know that, mass number = n + p.

Also, p = e.

Hence, p = mass number - e

So, Protons = 40 - 20 = 20.

(b) Atomic number = electrons

Hence, Atomic number = 20.

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Let's find out more:-

• The electronic configuration = 2, 8, 8, 2.

• The valence electrons = 2.

• Valency = 6.

• Will loose electrons.

• Element = Calcium.

• Will gain 2 positive charges after loosing electrons.

• It is a metal.

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