SC17 Groups in the Periodic Table

Question 1

How are elements arranged on the periodic table?

Answer 1

• arranged in increasing atomic number
• groups all have the same amount of electrons on the outermost shell
• periods have the same amount of electron shells

Question 2

What is group 1 called?

Answer 2

Alkali metals

Question 3

Why are alkali metals named alkali metals?

Answer 3

They form alkaline solutions when they react with water

Question 4

What are the physical properties of alkali metals?

Answer 4

• soft metals that can easily be cut with a knife
• relatively low densities and low melting points
• very reactive

Question 5

Write a word equation for the reaction of alkali metals with water

Answer 5

group 1 metal + water –> metal hydroxide + hydrogen

Question 6

Why are alkali metals reactive?

Answer 6

They only have one electron in the outermost shells, which can be lost easily

Question 7

Describe the reactivity of alkali metals

Answer 7

Reactivity increases as we go down the group

Question 8

Why does reactivity increase as we go down the group of alkali metals?

Answer 8

The atoms themselves get bigger, so it is easier to lose an electron because there are weaker forces of attraction between the outermost electron and the nucleus

Question 9

Describe the reaction of lithium with water

Answer 9

Fizzes steadily, slowly becomes smaller until it disappears

Question 10

Describe the reaction when sodium is added to water

Answer 10

Melts to form a ball, fizzes rapidly, quickly becomes smaller until it disappears

Question 11

Describe the reaction between potassium and water

Answer 11

Quickly melts to form a ball, burns violently with a lilac flame, disappears rapidly, often with a small explosion

Question 12

What is the name of group 7?

Answer 12

Halogens

Question 13

Describe the appearance of chlorine at room temperature

Answer 13

Pale yellow-green gas

Question 14

Describe the appearance of bromine at room temperature

Answer 14

red-brown liquid

Question 15

Describe the appearance of iodine at room temperature

Answer 15

Purple-black solid

Question 16

Describe the physical properties of halogens

Answer 16

• melting and boiling points increase as you go down the group
• diatomic molecules
• poor conductors of heat and electricity
• toxic and corrosive

Question 17

Why do melting and boiling points increase as you go down group 7?

Answer 17

The intermolecular forces increase as you go down the group, because the atoms get larger, so much more energy is required to get over these forces

Question 18

What is the test for chlorine gas?

Answer 18

It turns damp blue litmus paper white

Question 19

Describe the reactivity of halogens

Answer 19

Decreases as you go down the group

Question 20

Explain the reactivity of halogens

Answer 20

Decreases as you go down the group because its outer shell is further away from the nucleus, which means the electron is harder to take on due to weak intermolecular forces

Question 21

What does the halogen reaction with metals produce?

Answer 21

Metal halides

Question 22

What does the halogen reaction with hydrogen produce?

Answer 22

Hydrogen halides

Question 23

Describe the chemical properties of hydrogen halides

Answer 23

Becomes less stable as you go down the group

Question 24

When does a halogen displacement reaction occur?

Answer 24

When a more reactive halogen replaces a less reactive halogen

Question 25

How are displacement reactions examples of redox reactions?

Answer 25

One component is being oxidised whereas the other is being reduced

Question 26

What is group 0 called?

Answer 26

Noble gases

Question 27

Why are noble gases chemically inert?

Answer 27

They have full outer shells, and therefore do not react with other elements

Question 28

What are the physical properties of noble gases?

Answer 28

• low boiling points
• low densities
• colourless
• inflammable

Question 29

Why do boiling points increase as you go down the group of noble gases?

Answer 29

They have greater intermolecular forces that need to be overcome, due to the increase in electrons

Question 30

What is argon used for?

Answer 30

• provide an inert atmosphere for welding or electrical light bulbs
• advertising signs

Question 31

What is helium used for?

Answer 31

Filling weather and party balloons because it is less dense than air and does not burn

Question 32

What is fluorine used for?

Answer 32

Toothpastes

Question 33

What is chlorine used for?

Answer 33

• table salt
• bleaches
• water purification

Question 34

What is bromine used for?

Answer 34

As a disinfectant in swimming pools

Question 35

What is iodine used for?

Answer 35

• starch test
• antiseptics