F321 - The Periodic Table

Question 0

Why do the elements in a group have similar chemical properties?

Answer 0

They have similar outer shell electron configurations.

Question 1

What does the term periodicity mean?

Answer 1

A repeating pattern of properties across different periods.

Question 2

How did Mendeleev organise his periodic table?

Answer 2

By increasing atomic mass. He also arranged it according to repeating patterns of properties. He left spaces so that similar elements appeared in the same group. He then predicted what those elements’ properties would be.

Question 3

How did Newlands arrange his periodic table?

Answer 3

In order of increasing atomic mass where the eighth element is a repetition of the first. His periodic table was arranged in octaves.

Question 4

How did Dobereiner arrange his periodic table?

Answer 4

Arranged in triads where the middle of the three elements had an atomic mass that was a mean of the other two.

Question 5

How did Moseley arrange his periodic table?

Answer 5

Increasing number of protons in the nuclei of atoms of the elements.

Question 6

What is the periodic trend in ionisation energies?

Answer 6

Decrease down and group and increase across a period as nuclear charge increases across the period but electron shielding increases down a group.

Question 7

Why is there a drop in ionisation energy between groups 2 and 3?

Answer 7

Change from s to p subshells.

Question 8

Why is there a drop in ionisation energies between groups 5 and 6?

Answer 8

Starting to electron pair in the group 6 p orbital causing electron-pair repulsion.

Question 9

What is the trend for atomic radii on the periodic table?

Answer 9

Increases down a group and decreases across a period as the number of electron shells increases down a group but the attraction of the nuclear charge to the electrons is greater across a group as they are in the same outmost shell.

Question 10

How does the size of structures vary in the periodic table from left to right?

Answer 10

Giant metallic, giant molecular, simple molecular and individual atoms.

Question 11

What are the products from the slow reaction of a group 2 metal with water?

Answer 11

Metal hydroxide and hydrogen

Question 12

What are the products for a quick reaction of a group 2 metal and water?

Answer 12

Metal oxide and hydrogen.

Question 13

What is produced from the reaction if a group 2 metal with oxygen?

Answer 13

Metal oxide

Question 14

How does the reactivity of he element in group 2 vary?

Answer 14

Increasing reactivity down the group as it is easier to form cations (ionisation energies decrease) due to an increase in size, and electron shielding.

Question 15

What is the pH of the solution formed from dissolving a group 2 metal oxide in water?

Answer 15

Weakly alkaline

Question 16

Which type of reaction takes place when group 2 carbonates are heated?

Answer 16

Thermal decomposition

Question 17

What is magnesium hydroxide used for?

Answer 17

Indigestion tablets to neutralise excess acid in the stomach.

Question 18

What is calcium hydroxide used for?

Answer 18

Neutralise acidic soil to increase crop yield.

Question 19

Why do the boiling points of group 7 elements decrease down the group?

Answer 19

Stronger van der Waals’ forces as you go down the group as there is an increased number of electrons.

Question 20

What is the trend for reactivity down group 7? Why?

Answer 20

Decreases down the group. There is a decrease in the ease of making negative ions as the size of the atoms has increased meaning there is more shielding and less nuclear attraction.

Question 21

What does the term disproportionation mean?

Answer 21

A type of redox reaction in which the same species is both reduced and oxidised.

Question 22

How are halide ions tested for? What are the positive results?

Answer 22

Addition of silver nitrate and aqueous ammonia.
Silver nitrate:
Chloride - white precipitate
Bromide - cream precipitate
Iodide - yellow precipitate
Ammonia:
Chloride - dissolves in dilute
Bromide - dissolves in concentrated
Iodide - insoluble

Question 23

What is chlorine used for in drinking water?

Answer 23

Kill bacteria

Question 24

What are the disadvantages of using chlorine in drinking water?

Answer 24

Chlorine is highly toxic. It also reacts with traces if organic compounds in water which produce compounds that can cause cancer and act as mutagens.