This question is about metals.
(a) Metals are good electrical conductors.
State three other typical physical properties of metals.
(b) (i) Complete Table 6.1 to show the number of electrons, neutrons and protons in the potassium atom and the nickel ion shown.
(ii) Write the electronic configuration of the potassium atom.
(c) Choose one property from the list that shows that nickel is a transition element.
Tick (✓) one box.
- □ has a low density
- □ forms coloured compounds
- □ has a low melting point
- □ does not act as a catalyst
(d) Nickel can be manufactured by reducing nickel(II) oxide with carbon monoxide and hydrogen.
\[ 2NiO + CO + H_2 \rightarrow 2Ni + H_2O + CO_2 \]
Explain how this equation shows that nickel(II) oxide is reduced.
(e) Table 6.2 shows the observations when four different metals are heated with steam.
Put the four metals in order of their reactivity.
Put the least reactive metal first.
▶️ Answer/Explanation
(a) Any three of:
- Malleable (can be hammered into sheets)
- Ductile (can be drawn into wires)
- High melting point / high boiling point
- Good thermal conductor
- Shiny/lustrous appearance
- Sonorous (produces ringing sound when struck)
(b)(i) Table 6.1 completed:
| number of electrons | number of neutrons | number of protons | |
|---|---|---|---|
| 41K | 19 | 22 (41-19) | 19 |
| 62Ni2+ | 26 (28-2) | 34 | 28 |
For potassium: Neutrons = mass number (41) – atomic number (19) = 22. Protons = atomic number = 19.
For nickel ion: Protons = atomic number = 28. Electrons = atomic number (28) – charge (2+) = 26.
(b)(ii) Electronic configuration of potassium: 2,8,8,1
Potassium (K) has atomic number 19, so its electron arrangement is: 2 electrons in first shell, 8 in second, 8 in third, and 1 in outer shell.
(c) Second box ticked: “forms coloured compounds”
This is a characteristic property of transition elements like nickel. They form colored compounds due to the presence of partially filled d-orbitals.
(d) Nickel(II) oxide loses oxygen
In the reaction, nickel(II) oxide (NiO) is converted to nickel (Ni), meaning it loses oxygen. This is the definition of reduction (loss of oxygen).
(e) Order of reactivity: niobium < copper < chromium < magnesium
The rate of oxide formation indicates reactivity with steam/oxygen. Magnesium reacts most rapidly, followed by chromium, then copper. Niobium doesn’t react at all, making it least reactive.
This question is about metals.
(a) Many metals have high melting points and boiling points.
State three other typical physical properties of metals.
(b) (i) Complete Table 6.1 to show the number of electrons, neutrons and protons in the sodium atom and silver ion shown.
(ii) Write the electronic configuration of the sodium atom.
(c) Silver is a transition element. Sodium is in Group I of the Periodic Table.
State one difference in the physical properties of silver and sodium.
(d) Table 6.2 shows the observations when four different metals are heated in oxygen.
Put the four metals in order of their reactivity.
Put the least reactive metal first.
(e) Copper(II) oxide is reduced by carbon monoxide.
\( \text{CuO} + \text{CO} \rightarrow \text{Cu} + \text{CO}_2 \)
Explain how this equation shows that copper(II) oxide is reduced.
▶️ Answer/Explanation
(a) Any three of:
- Malleable (can be hammered into sheets)
- Ductile (can be drawn into wires)
- Good electrical conductors
- Good thermal conductors
- Shiny/lustrous appearance
- High density
(b)(i)
For sodium atom (\( \frac{23}{11}\text{Na} \)):
- Number of neutrons = Mass number – Atomic number = 23 – 11 = 12
- Number of protons = Atomic number = 11
For silver ion (\( \frac{109}{47}\text{Ag}^+ \)):
- Number of electrons = Atomic number – charge = 47 – 1 = 46
- Number of protons = Atomic number = 47
Completed table:
| number of electrons | number of neutrons | number of protons | |
|---|---|---|---|
| \( \frac{23}{11}\text{Na} \) | 11 | 12 | 11 |
| \( \frac{109}{47}\text{Ag}^+ \) | 46 | 62 | 47 |
(b)(ii) Electronic configuration of sodium atom: 2,8,1
(This represents the distribution of electrons in the K, L, and M shells respectively)
(c) Any one difference:
- Silver has higher density than sodium
- Silver has higher melting point than sodium
- Silver forms colored compounds while sodium compounds are typically white
- Silver is less reactive than sodium
(d) Order of reactivity: silver < copper < lanthanum < cerium
Explanation:
- Silver shows no reaction (least reactive)
- Copper reacts very slowly
- Lanthanum reacts rapidly but doesn’t burn
- Cerium burns rapidly (most reactive)
(e) Copper(II) oxide loses oxygen (to form copper metal), which is the definition of reduction.
In the reaction: CuO → Cu, the copper oxide is losing oxygen, so it’s being reduced. The carbon monoxide is acting as the reducing agent by removing oxygen from the copper oxide.