8. The Periodic Table

Question 1

Describe the Periodic Table

Answer 1

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

Question 2

Describe the change from metallic to
non-metallic character across a period

Answer 2

Metallic character of the elements decreases across a period, from left to right, and it increases down a Group

Question 3

Describe the relationship between group number and the charge of the ions formed from elements in that group

Answer 3

Group number can help determine the charge of the ions (G1-3 +ve, 6-7 -ve)

Question 4

Explain similarities in the chemical properties of elements in the same group of the Periodic Table in terms of their electronic configuration

Question 5

Explain how the position of an element in the Periodic Table can be used to predict its properties

Answer 5

Using its group number and period number helps in the prediction of the properties of an element e.g. its reactivity

Question 6

How to identify trends in groups by using the given information about the elements

Answer 6

• Using given information about the elements helps in identifying the trend
  E.g. reaction of Group 1 elements with water shows that reactivity increases as you go down the group

Question 7

Describe the Group I alkali metals as relatively soft metals with general trends down the group

Answer 7

General trends:
1. Density increases down the group
2. M.P decreases down the group
3. Reactivity increases down the group

Question 8

Describe the Group VII halogens, chlorine, bromine and iodine, as diatomic non-metals with general trends down the group

Answer 8

1. M.P and B.P increases down the group
2. Reactivity decreases down the group
3. Density increases down the group so does the physical state
4. Colour darkens down the group

Question 9

State the appearance of the halogens at r.t.p.

Answer 9

1. Chlorine: Pale yellow-green gas
2. Bromine: Red-brown liquid
3. Iodine: Grey-black solid (Iodine vapour: Purple, Aqueous iodine: Brown)

Question 10

Describe and explain the displacement reactions of halogens with other halide ions

Answer 10

• When a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide
• Least reactive halogen ends up in the elemental form
• More reactive halogen displaces the least reactive
• E.g. potassium bromide + chlorine → potassium chloride + bromine

Question 11

Describe transition metals by stating its properties

Answer 11

1. Have high densities
2. Have high melting points
3. Form coloured compounds
4. Often act as catalysts as elements and in compounds

Question 12

Describe transition elements as having ions with variable oxidation number

Answer 12

• Transition elements have more than one oxidation number, as they can lose a different number of electrons
• Different oxidation states will have different properties and colours

Question 13

Describe the Group VIII noble gases and explain why its unreactive in terms of electronic configuration

Answer 13

Group 8: Group 0 are monatomic, colourless gases
- They all have full outer shells since its electronic configuration is extremely stable so these elements are unreactive and inert