Periodicity

Question 1

How does atomic radius change across a period

Answer 1

Decreases as increasing nuclear charge pulls electrons closer together as there’s an increase in electrostatic attraction

Question 2

How does atomic radius change down a group

Answer 2

It increases as a new shell is added each period increasing shielding therfore decreasing attraction

Question 3

How does ionisation change across a period

Answer 3

It increases as the decreasing atomic radius means the electrostatic forces of attraction are stronger meaning more energy is required to remove an electron.

There’s a decrease from group 2 to 3 due to the electron comping from a P shell instead of an s so less energy is required to remove it

There is also a decrease from group 5 to 6 as in group 5 each electron is in its own seperate 2p orbital wheras in group 6 2 electrons must share an orbital causing electron pair repulsion making it easier to remove

Question 4

How does ionisation energy change down a group

Answer 4

It decreases as nuclear attraction decreases making it easier to remove an electron

Question 5

How does melting point change across group 3

Answer 5

Na, Mg , Al are all metallically bonded increasing in strength due to increase in charge so more electrons are demoralised.

Silicone has a very strong giant covalent structure giving it the highest melting point as the bonds are difficult to overcome.

P, S, Cl are all simple covalent structures held together by van der walls forces which are easily overcome.

Argon is a monotomic molecule and has a full outer shell making it inhert so bam der walls forces between them are extremely weak.