Question

The number of electrone in an element with atomic number Z and mass number A will be:(1) A-Z (2) Z-A (3) Z+A (4) none of these​

Answer 1

Answer :-

None of these

Explanation :-

According to the question,

• Atomic number = Z
• Mass number = A

Atomic number:

★ Atomic number indicates the number of electrons present in the atom of an element.

★ Atomic number of any element is represented as Z

★ In a neutral element i.e. when the atom has not gained or lost any electrons,

Number of protons = Number of electrons

Mass number:

♦ Mass number is the average atomic mass of the atom.

♦ It is represented by the alphabet ‘A’

♦ In a neutral atom,

Mass Number = Number of protons + Number of neutrons

Number of neutrons can be written as A - Z but not the number of electrons.

So, (d) Option is the correct answer.