Topic 8

Question 1

Periodic table

Answer 1

An arrangement of elements in periods and groups in order of increasing proton/atomic number

Question 2

Periodic trends: metallic character

Answer 2

Decreases as you move across period (left to right)

Question 3

Periodic trends: group number

Answer 3

Corresponds number of outermost electrons + tells us charge -> group 1 elements from 1+ ions and Group 7 elements from 1-

Question 4

Periodic trends: elements in the same group

Answer 4

Similar chemical properties -> due to having the same number of electrons in their outer shell (chemical peoperties depend on outermost electrons)

Question 5

Physical properties of alakli metals (group 1)

Answer 5

• Silvery coloured metals
• Soft -> easily cut with a knife
• Low melting and boiling point
• Low densisties

Question 6

Chemical properties of alkali metals (group 1)

Answer 6

• highly reactive metals
• oxidises easily
• reactivity increases on descending the group

Question 7

Observations of reaction with water (group 1 metals) -> lithium

Answer 7

• when cut it reveals a shiny surface
• fizzing, floating
• when adding universal indicator it turns blue/purple
• positive test for hydrogen

Question 8

Observations of reaction with water (group 1 metals) -> sodium

Answer 8

• floating around surface, fizzing
• turns into a perfect sphere as its melting
• when adding universal indicator, turns blue/purple
• positive test for hydrogen

Question 9

Observations of reaction with water (group 1 metals) -> potassium

Answer 9

• lilac flame
• floating, moving faster
• fizzing
• forms sphere

Question 10

Equation of reaction of group 1 metal with water

Answer 10

Metal + water -> metal hydroxide + hydrogen

Question 11

KEY PROPERTIES metal group 1 -> melting point

Answer 11

• as you go down group 1, the melting point decreases due to weaker forces of attraction (between metal atoms)

Question 12

KEY PROPERTIES metal group 1 -> denisty

Answer 12

• As you go down group 1, denisty increases

Question 13

KEY PROPERTIES metal group 1 -> reactivity

Answer 13

As you go down group 1 reactivity increases because:
- greater distance between nucleus and outer shell electron
- attraction becomes weaker (nuclear attraction)
- greater shielding effect
- atoms get larger
SO: EASIER TO LOSE OUTER SHELL ELECTRON

Question 14

Halogens (group 7)

Answer 14

• Increasing denisty
• non-metals so don’t conduct electricty
• exist as diatomic molecules
• decreasing reactivity

Question 15

Physical state of halogens changes as you go down the group -> chlorine

Answer 15

Pale yellow-green gas

Question 16

Physical state of halogens changes as you go down the group -> flourine

Answer 16

Yellow gas

Question 17

Physical state of halogens changes as you go down the group -> bromine

Answer 17

Red/brown liquid

Question 18

Physical state of halogens changes as you go down the group -> iodine

Answer 18

Grey/black solod

Question 19

Group 7 elements get LESS reactive as you go down the group because?

Answer 19

• larger atoms
• weaker attraction between nucleus and outer shell (nuclear attraction)
• greater shielding effect
• HARDER to gain electron

Question 20

Properties of transition metals

Answer 20

• high densities -> higher than grouo 1 alkali metals
• high melting points -> higher than group 1 alkali metals
• stronger than group 1 alkali metals
• form coloured compounds
• often act as catalysts as elements in compounds
• hard, strong and brittle

Question 21

Noble gasses (group 0 elements)

Answer 21

• unreactive and don’t easily form molecules -> have a full outer shell
• stable arrangements of electrons
• all of them have 8e- in outer shell, except helium which has 2

Question 22

Uses of noble gasses

Answer 22

• neon lights
• manufactiring of halogen headlights