Periodic Table

Question 1

Describe the EC & acid-base character of metal oxides?

Answer 1

Metals - conduct electricity - charge flows easily.
Basic - neutralise acids - dissolve to form pH > 7

Question 2

Describe the EC & acid-base character of non-metal oxides?

Answer 2

Non-metals - poor conductors.
Non-metal oxides - acidic - neutralise bases - dissolve to form pH < 7.

Question 3

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

Answer 3

Same group - same number of electrons in outer shell - similar properties.

Question 4

Why do the noble gases not easily react?

Answer 4

Inert - full outer shells - as lots of energy to add/remove atoms.

Question 5

Describe the reactions of Group 1 Alkali Metals with water & oxygen?

Answer 5

Li/Na/K all react vigorously with water - metal hydroxide produced - alkaline.
Hydrogen also produced in reaction with water - fizzing.

Oxygen - Group 1 metals form metal oxides.

Question 6

Describe the differences between reactions of Group 1 metals with oxygen & water.

Answer 6

Descend Group 1 - elements more reactive.
Rate of reaction increases - lithium takes longer than Na/K to react with water.
Oxygen - K reacts to form oxide quicker than Na/Li.

Question 7

Explain the trend in reactivity of Group 1 in terms of electronic configurations?

Answer 7

Group 1 metals - 1 electron outer shell.
Descend Group 1 - outermost electron furthest from nucleus.
So less attraction between outermost electron & nucleus.
So as atoms get bigger - outermost electron lost most easily - metals more reactive.

Question 8

Describe the colour/physical state (RTP) of Chlorine?

Answer 8

Cl2 - reactive, poisonous, green gas.

Question 9

Describe the colour/physical state (RTP) of Bromine?

Answer 9

Br2 - poisonous, red-brown liquid - gives off orange vapour.

Question 10

Describe the colour/physical state (RTP) of Iodine?

Answer 10

I2 - dark-grey crystalline solid - purple vapour when heated.

Question 11

Describe the trends of halogens?

Answer 11

As atomic number increases - darker colour & higher boiling point.
As we descend group - reactivity decreases.

Question 12

What is a displacement reaction?

Answer 12

More reactive element displaces less reactive element.
E.g. Cl2 more reactive than I2 (higher up Group 7).
Add Cl2 to KI solution - Cl2 reacts with potassium - forms potassium chloride.
Iodine displaced & left in solution - turned brown.

Question 13

Few drops halogen solution added to KI - solution turned brown. How to find halogen solution?

Answer 13

Add halogen solution to KBr.
If solution turns orange - chlorine & if no reaction - bromine.

Question 14

What does an oxidising & reducing agent do?

Answer 14

Oxidising agent - Accepts electrons - gets reduced - becomes oxidising agent.
Reducing agent - donates electrons - gets oxidised - becomes reducing agent.

Question 15

What is oxidation & reduction?

Answer 15

Oxidation - loss of electrons.
Reduction - gain of electrons.

Question 16

Explain the trend in reactivity of group 7 in terms of electronic configurations?

Answer 16

Group 7 - 7 electrons outer shell - gain 1 electron to form 1- ion.
Descend Group 7 - number of electron shells increases - halogens less reactive - harder to attract extra electron to fill outer shell when further from nucleus - as more energy to join.