C2 The periodic table

Question 1

State the name of the elements in Group 1

Answer 1

Alkali metals

Question 2

Properties of the alkali metals

Answer 2

• Very reactive, their reactivity increases as you go down the group
• Very low density compared to other metals
• Very soft
• From metal ions carrying a 1+ charge and always form ionic compounds
• Relatively low melting and boiling points, decreases as you go down the group

Question 3

Reactions of alkali metals

Answer 3

• The metals all react with water to produce hydrogen and an alkaline solution containing the metal hydroxide
• Potassium reacts so vigorously with water that the hydrogen produced ignites, it burns with a lilac flame
• The alkali metals also react vigorously with non-metals such as chlorine gas, they produce metal chlorides which are white solids
• From metal ions carrying a 1+ charge and always form ionic compounds, these are generally white and dissolve in water, giving colourless solutions

Question 4

State the name of the elements in Group 7

Answer 4

The halogens

Question 5

Properties of the halogens

Answer 5

• Low melting and boiling points, increase going down the group
• Poor conductors of heat and electricity

Question 6

Reactions of halogens

Answer 6

• Form covalent compounds by sharing electrons with other non-metals
• A more reactive halogen can displace a less reactive halogen from a solution of one of its salts
• The reactivity of the halogens decreases going down the group

Question 7

Explain why the reactivity of elements changes going down Group 1

Answer 7

• Reactivity increases going down the group
• Because the atoms get larger
• So there is less attraction between the nucleus and the outer shell
• So the atom loses an electron more easily

Question 8

Explain why the reactivity of elements changes going down Group 7

Answer 8

• Reactivity decreases going down the group
• Because the atoms get larger
• So there is less attraction between the nucleus and the outer shell
• So it is harder for the atom to gain an electron

Question 9

Describe the physical properties of transition elements

Answer 9

• Good conductors of electricity and thermal energy
• Hard and strong
• High densities
• High melting points, with the exception of mercury, Hg, which is a liquid at room temperature

Question 10

Describe the chemical properties of transition elements

Answer 10

• Much less reactive than the alkali metals
• Do not react vigorously with oxygen or water

Question 11

Compounds of transition elements

Answer 11

A transition element can form ions with different charges, in compounds that are often coloured
- copper(II) sulphate is blue (due to its Cu(2+) ions)
- nickel(II) carbonate is pale green (due to its Ni(2+) ions)
- magnesium(II) chloride is pale pink (due to its Mg(2+) ions)

Question 12

Uses of transition elements

Answer 12

Transition elements and their compounds are important industrial catalysts