Question

The ion of an element has 2 positive charge. Mass number of the atom is 24 and
the number of neutrons is 12. What is the number of electrons in ions?​

Answer 1

Answer:

10 electrons

Mass number = no. of protons + no. of neutons

24 = no. of protons + 12

24-12= no. of protons

12 = no. of protons

no.of protons=no.of electrons

BUT, The ion has 2 positive charge. That means 2 electrons have been given away.

So, number of electrons= no. of protons-2

no. of electrons= 12-2=10

Answer 2

Question : The ion of an atom have 2 negative charge. Mass number of the atom is 16 and the number of neutrons are 8.What is the number of electrons in the ion ?

a] 6

b] 7

c] 8

d] 10

Given :

Mass number of the atom = 16

Number of neutrons = 8

Charge of the ion = -2

To Find : Number of electrons in the ion

Solution :

Mass number is given by ,

★ Mass number = Number of protons + Number of neutrons

We have ,  

Mass number = 16

Number of neutrons = 8

⇒ Number of protons + 8 = 16

⇒ Number of protons = 16 - 8

⇒ Number of protons = 8

Number of protons = Number of electrons in neutral atom

⇒ Number of electrons in the given atom (when it is neutral) = 8

We are given that the atom acquired -2 charge on it . This mean the atom has gained 2e⁻. So , Now the electrons in the given ion should be 10  

∴ The Electrons in the given ion is 10

Hence , option(d) is correct