Patterns in the Periodic Table

Question 0

Why does the atomic radius increase down a group?

Answer 0

Outer electrons enter new energy levels so are further away and screened by electron shells.
This means the electrons aren’t held as tightly.

Question 1

Why does the atomic radius decrease across a period?

Answer 1

The nuclear charge becomes more positive due to an increase in protons.
Electrons also increase but are in same shell so are attracted more strongly to the nucleus.

Question 2

How big is the ionic radius of a positive ion compared to its element?

Answer 2

Smaller due to loss of electron(s).

Question 3

How big is the ionic radius of a negative ion compared to its element?

Answer 3

Larger due to gaining electron(s).

Question 4

What is the first ionisation energy directly related to?

Answer 4

The attraction of the nucleus for the most loosely bound of the outer electrons.

Question 5

What are the 3 main factors that affect the ionisation energy of an atom?

Answer 5

1. The attraction between the nucleus and the outermost electron.
2. The size of the positive nuclear charge.
3. Inner shells of electrons repel the outer electron, shielding it from the nucleus.

Question 6

What affects the attraction between the nucleus and the outermost electron?

Answer 6

Distance decreases the attraction.