Science Applic

Number of electrons = Number of protons

Let there be ‘a’ number of protons and ‘a’ number of electrons.

And, charge on 1 proton = +1

Then, charge on ‘a’ protons = 1 × a = a

Charge on electron = -1

Then, charge on ‘a’ electrons = -1 × a = -a

⇒ Total charge = Charge on ‘a’ protons + Charge on ‘a’ electrons

⇒ Total charge = a + (-a)

⇒ Total charge = 0

Thus, charge of an atom when there are equal number of electrons and protons is 0.

(b) Let the atom have ‘a’ number of electrons and ‘a’ number of protons.

If an atom loses an electron, it is left with (a – 1) electrons.

Number of protons = a

Now, charge on 1 electron = -1

⇒ Charge on ‘(a – 1)’ electrons = -1 × (a – 1)

⇒ Charge on ‘(a – 1)’ electrons = -(a – 1)

⇒ Charge on ‘(a – 1)’ electrons = (1 – a)

Charge on 1 proton = 1

⇒ Charge on ‘a’ protons = 1 × a

⇒ Charge on ‘a’ protons = a

Total charge on atom = (1 – a) + a

⇒ Total charge on atom = 1

(c) Let the atom have ‘a’ number of electrons and ‘a’ number of protons.

If an atom gains an electron, it becomes (a + 1) electrons.

Number of protons = a

Now, charge on 1 electron = -1

⇒ Charge on ‘(a + 1)’ electrons = -1 × (a + 1)

⇒ Charge on ‘(a + 1)’ electrons = -(a + 1)

Charge on 1 proton = 1

⇒ Charge on ‘a’ protons = 1 × a

⇒ Charge on ‘a’ protons = a

Total charge on atom = -(1 + a) + a

⇒ Total charge on atom = -1 – a + a

⇒ Total charge on atom = -1