Topic 7: Periodic Trends, Video B: Ionic Size

Question 1

Cations are always smaller or larger than the atoms they come from?

Answer 1

Smaller because their outer shell is lost.

Question 2

Anions are always smaller or larger than the atoms they come from?

Answer 2

Larger because their electronic cloud gets bigger because there are more electrons that cause a greater repellence.

Question 3

Isolectronic ions and atoms have the same number of electrons or protons?

Answer 3

Electrons.

Question 4

Are all ions isolectronic?

Answer 4

Yes, some ions gain electrons, and some loose electrons.

Question 5

For isolectronic ions does the radius decrease or increase with increasing atomic number and why?

Answer 5

The radius decreases because the number of protons is increasing but the electrons stay the same. Therefore the ion with more protons has a stronger pull on the electrons and therefore shrinks the electron cloud making the ion smaller.

Question 6

What’s an ion?

Answer 6

An atom or molecule with a net electric charge due to the loss or gain of electrons.