Periodicity

Question 1

How are atoms in the periodic table arranged?

Answer 1

Increasing atomic number

Question 2

How is the periodic table arranged into blocks?

Answer 2

Question 3

What is the full electron configuration of Na?

Answer 3

Question 4

What is the full electron configuration for Si?

Answer 4

Question 5

What is the general trend in first ionisation energies across a period?

Answer 5

Increases

Question 6

What are the anomalies in the trend for first ionisation energies across a period?

Answer 6

There is a dip between group 2 and 3 and another dip between group 5 and 6.

Question 7

Why does the first ionisation energy increse across a period?

Answer 7

As you go along a period the electron being removed is:

• in the same shell so shielding is similar
• there are more protons in the nucleus so the attraction is greater

So the nuclear attraction to the outer shell electrons is greater and so takes more energy to remove it

Question 8

Describe the trend for atomic radius across a period? Why?

Answer 8

Decreases

• Shielding is similar as there is the same number of shells
• Distance decreases as there are more protons in the nucleaus and so the electrons are held more tightly.

Question 9

Describe the trend of size of positive ionic radius (compares to their atoms) across a period. Why?

Answer 9

Smaller

-There are the same number of protons attracting fewer electrons and so they are held more tightly. This decreases distance, meaning the radius is smaller.

Question 10

Describe the trend in size of negative ionic radius (compared to their atoms) across a period. Why?

Answer 10

Larger

-Same number of protons attracting more electrons therefore they are held less tightly. This means the distance increases and so ionic radius increases.

Question 11

Describe the trend in electronegitivity as you go across a period. Why?

Answer 11

Increases

• There is the same number of shells and so similar shielding
• The are more protons in the nucleus and so the nuclear charge will increase. This pulls the electrons more tightly.

Therefore the pair of electrons in the covalent bonds are more strongly attracted.

Question 12

Describe the stucture and bonding in period 3 (Na - Al) and what does this mean for the size of the boiling point? (Include a diagram)

Answer 12

Question 13

Describe the structure and bonding in silicon. (Include a diagram)

Answer 13

Question 14

Describe the structure in P4, S8 and Cl2. Compare them relative to each other.

Answer 14

Question 15

Describe the structure of Ar.

Answer 15

Structure: Simple atomic

V. weak Van Der Waals forces between atoms