2 - The Periodic Table

Question 1

What is the history of the periodic table?

Answer 1

1. John Dalton was one of the first to arrange the elements in the periodic table in order of weight
2. John Newlands created a ‘law of octaves’ as he noticed a pattern with every eighth element
3. Dmitri Mendeleev arranged the 50 discovered elements and left gaps for undiscovered elements
4. At the start of the 20th century, scientists found out more about the structure of the atom and filled the gaps

Question 2

What are the features of metals?

Answer 2

• conduct electricity
• higher melting and boiling points
• more pliable & malleable

Question 3

What are the features of non metals?

Answer 3

• electrical insulators
• lower melting & boiling points
• more brittle

Question 4

What are the features of noble gases?

Answer 4

• noble gases are monatomic gases
• they don’t reach due to their stable electronic structure
• the boiling points increase as you go down

Question 5

What are the properties of the Alkali metals?

Answer 5

• very reactive, must be stored in oil to prevent reaction with oxygen
• reactivity increases as you go down
• low density
• soft
• shiny surface until reacted with oxygen
• burn vigorously in oxygen, forming white smoke of their oxides
• soluble in water, colourless with high pH
• relatively low m.p & b.p compared to other metals

Question 6

Alkali metal + water = ?

Answer 6

Metal hydroxide, hydrogen gas is formed = fizzing

Question 7

Alkali metal + chlorine gas = ?

Answer 7

Metal chloride, white solids that dissolve in water to form colourless solutions

Question 8

What are the properties of the alkali metals?

Answer 8

• toxic non metals with coloured vapours
• low m.p & b.p, increase as you go down
• poor conductors of heat & electricity
• more reactive halogens displace less reactive halogens from solutions of its salts, the colour of the final solution is least reactive halogen as an (aq) molecule

Question 9

How are halogens found as elements?

Answer 9

As diatomic molecules, joined by a covalent bond.

Question 10

What are the properties of the transition metals?

Answer 10

• good conductors of electricity & heat
• hard, strong & dense
• high melting points, except mercury
• less reactive
• slow corrosion
• good structural materials

Question 11

What coloured compounds do the transition elements form?

Answer 11

Copper (II) sulfate - blue
Nickel (II) carbonate - pale green
Chromium (III) oxide - dark green
Manganese (II) chloride - pale pink

Question 12

Why do transition elements usually carry a Roman numeral?

Answer 12

They can form more than one ion.

Question 13

Which transition elements are most commonly used as catalysts?

Answer 13

Nickel - to make margarine

Iron - to make ammonia in the Haber process