Topic 6 - Groups in the Periodic Table

Question 1

Why do the elements in Group 1 have similar chemical properties?

Answer 1

They all have 1 outer electron

Question 2

What is Group 1 called?

Answer 2

Alkalai Metals

Question 3

What are the Group 1 Physical Properties

Answer 3

Low melting and boiling points ( comp to other metals)
Very soft

Question 4

What bonds do Group 1 elements form?

Answer 4

Ionic, no covalent bonds

Question 5

Why doesnt group 1 form covalent bonds?

Answer 5

They only have 1 outer electron so it is lost very easily, there is no point of sharing it

Question 6

What ions do group 1 form?

Answer 6

+1

Question 7

What makes a metal reactive?

Answer 7

the more readily a metal looses their outer electrons, this makes group 1 ( with only 1 outer electron ), very reactive

Question 8

Why are metals more reactive with water ( or dilute acid ) as you go down a group?

Answer 8

Their outer electrons are further out, having more shells in between them. This makes the electron less strongly bonded the the nucleus and less energy is needed to remove it.

Question 9

What happens when Alkali Metals (group 1) react with water?

Answer 9

A hydroxide and a hydrogen gas

They react vigorously, forming an ionic compound

Question 10

Write the balanced equation for sodium reacting with cold water

Answer 10

2Na + 2H₂O –> 2NaOH + H₂

Sodium + water —> Sodium hydroxide + water

Question 11

Lithium’s reaction with water

Answer 11

Move around the surface, Fizzing furiously

Question 12

Sodium and Potassium reactions with water.

Answer 12

Same as lithium, but they also melt in the heat of the reaction.
Potassium often gets hot enough to ignite the hydrogen produced.

Question 13

WHat are group 7 elements known as?

Answer 13

Halogens

Question 14

Why do group elements have similar properties?

Answer 14

They all have the same number of outer electrons

Question 15

How do halogens exist chemically?

Answer 15

In Diatonic Molecules, sharing one pair of electrons in a covalent bond giving both atoms a full outer shell

Question 16

What are the physical properties of Group 7 elements?

Answer 16

The melting and boiling points increase as you go down the group

Question 17

Why do the melting/boiling points increase as you go down group 7 molecules?

Answer 17

The Molecules get bigger due to more shells, this creates stronger intra-molecular forces meanign more energy is needed to break them apart

Question 18

What is Chlorine at room temperature?

Answer 18

a fairly reactive, poisonous, green GAS

Question 19

What is Bromine at room temperature?

Answer 19

a poisonous red-brown liquid, which gives off an orange vapour at room temperature.

Question 20

What is iodine at room temperature?

Answer 20

a dark grey crystalline solid which gives off a purple vapour when heated.

Question 21

How do you test a gas for Chlorine?

Answer 21

Damp Blue Litmus Paper
- Chlorine will bleach the litmus paper, turning it white.
- ( it may turn it red first as it is acidic)

Question 22

How does reactivity work in Group 7?

Answer 22

It is less as you go down the group.
Halogens need to gain an electron, as more shells are gained the attraction to the nucleus is less, making it harder to attract and electron.

Question 23

What makes a Halogen reactive?

Answer 23

the Easier it is to attract an electron

Question 24

What is the reaction of Halogens with metals?

Answer 24

Halogen + Metal –> Metal Halide (Salt)

Question 25

Why are halogens higher in the group more reactive with metals?

Answer 25

The attract the outer shell of the metal more easily.

Question 26

What is the reaction of halogens and Hydrogen?

Answer 26

Halogen + Hydrogen -> hydrogen halides

Question 27

Properties of hydrogen halides?

Answer 27

Soluble, and can dissolve in water to form acidic solutions.
Hydrogen chloride -> Hydrochoric acid

Question 28

What is a displacement reaction?

Answer 28

Where a more reactive element displaces a less reactive element from a compound

Question 29

What are halogen displacement reactions?

Answer 29

Redox reactions

Question 30

WHat happens in a halogen displacement reaction?

Answer 30

The halogens gain electrons, whilst halide ions loose electrons

A higher period halogen will displace the halide

Question 31

Why does the solution turn orange when chlorine reacts with potassium bromide

Answer 31

the chlorine displaces the bromide and the bromine is released therefore turns the solution orange

Question 32

Displacement reactions halogens experement

Answer 32

Mesure out a small amount of halide salt solution into a test tube
Add a few drops of halogen solution to it and shake it gently
If a color change is observed, a reaction has happened

Question 33

reactivity in halogens

Answer 33

less reactive as you go down the group

Question 34

What are the group 0 elements called?

Answer 34

Noble gases

Question 35

What are noble gases typical features at room temp

Answer 35

colourless gases
monatomic
inert - dont react alot (full outer shell of electrons)
non-flammable
hard to observe

Question 36

Uses of noble gases

Answer 36

• used to provide an inert atmosphere
• Argon in filament lamps
• Argon and helium in welding
• Helium in airships (lower density than air) - non flammable so better than hydrogen

Question 37

Argon in filament lamps

Answer 37

non-flammable, so stops filament from burning away
( same principle for flash photography)

Question 38

Argon and helium in welding

Answer 38

Protecting metals whilst welding, inert atmosphere protects the hot metal from reacting with the oxygen

Question 39

Trends in properties of noble gases

Answer 39

Boiling point, melting point and density all decrease as you go down the group