Group Properties & Trends (Cambridge (CIE) IGCSE Co-ordinated Sciences (Double Award): Chemistry): Flashcards
Exam code: 0654 & 0973
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- FrontGroup I Properties
Why are Group I metals called the alkali metals?
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Cards in this collection (34)
Why are Group I metals called the alkali metals?
They are called alkali metals because they react with water to form alkaline solutions with a high pH.
Group I metals react with water to produce a metal ______ solution and ______ gas.
Group I metals react with water to produce a metal hydroxide solution and hydrogen gas.
True or False?
Reactivity of Group I metals decreases as you go down the group.
False.
Reactivity of Group I metals increases going down the group, so potassium reacts more vigorously with water than lithium.
Why are Group I metals stored under oil?
Group I metals are stored under oil to prevent them from reacting with oxygen and water vapour in the air.
Going down Group I, melting point ______ and reactivity with water ______.
Going down Group I, melting point decreases and reactivity with water increases.
What is the distinguishing observation when potassium reacts with water, compared with sodium?
Potassium reacts more vigorously than sodium and burns with a lilac flame on the surface of the water.
Why does reactivity increase going down Group I?
Reactivity increases because the outer electron is further from the nucleus in each successive element, so it is more easily lost when the metal reacts.
What does "diatomic" mean and which Group VII elements are diatomic?
Diatomic means forming molecules of two atoms. All halogens are diatomic: Cl2, Br2 and I2 are common examples.
At room temperature, chlorine is a ______ gas, bromine is a ______ liquid and iodine is a ______ solid.
At room temperature, chlorine is a pale yellow-green gas, bromine is a red-brown liquid and iodine is a grey-black solid.
True or False?
Reactivity of Group VII elements increases going down the group.
False.
Reactivity of Group VII elements decreases going down the group, because the outer shell is further from the nucleus and harder to attract an incoming electron.
Why does reactivity decrease going down Group VII?
Going down Group VII, the atomic radius increases and there is greater electron shielding, so the nucleus attracts an incoming electron less strongly and it becomes harder to gain the outer electron needed to react.
Going down Group VII, melting point ______, density ______ and colour becomes ______.
Going down Group VII, melting point increases, density increases and colour becomes darker.
What charge do halide ions carry and how is this charge achieved?
Halide ions carry a 1- charge. Each halogen atom gains one electron to complete its outer shell of 8 electrons.
What are the three colours of iodine in its different forms: solid, vapour and aqueous solution?
Solid iodine is grey-black, iodine vapour is purple and aqueous iodine is brown.
What is a halogen displacement reaction?
A halogen displacement reaction is one in which a more reactive halogen displaces a less reactive halogen from an aqueous solution of its halide salt.
When Cl2 (aq) is added to KBr (aq), the solution turns ______ because ______ is displaced.
When Cl2 (aq) is added to KBr (aq), the solution turns orange because bromine is displaced.
True or False?
Iodine can displace bromine from a solution of potassium bromide.
False.
Iodine is less reactive than bromine, so it cannot displace bromine. Only a more reactive halogen can displace a less reactive one.
Why can chlorine displace bromide ions from solution?
Chlorine is more reactive than bromine so it can oxidise bromide ions, gaining electrons to form chloride ions and releasing bromine.
The ionic equation for chlorine displacing bromide ions is:
2Br- (aq) + Cl2 (aq) → ______ (aq) + ______ (aq)
The ionic equation for chlorine displacing bromide ions is:
2Br- (aq) + Cl2 (aq) → 2Cl- (aq) + Br2 (aq)
What colour change is observed when bromine solution is added to potassium iodide solution, and what does this indicate?
The solution turns brown, indicating that bromine has displaced iodide ions to form iodine, I2, which is more reactive than iodine.
How does reactivity order of chlorine, bromine and iodine determine the outcome of a displacement reaction?
Chlorine is the most reactive and iodine the least. A halogen will only displace a halide ion that is lower in reactivity, so chlorine displaces both bromide and iodide while bromine only displaces iodide.
Where are the transition elements found in the Periodic Table?
Transition elements are found in the central block of the Periodic Table, between Group 2 and Group 3.
Transition elements form ions with ______ charges, produce ______ compounds and are useful as ______.
Transition elements form ions with variable charges, produce coloured compounds and are useful as catalysts.
True or False?
All transition elements have high melting points.
False.
Most transition elements have high melting points, but mercury is an exception: it has a low melting point and is a liquid at room temperature.
What two oxidation states does iron commonly form, and what is the significance of transition elements having variable oxidation states?
Iron forms Fe2+ and Fe3+ ions. Variable oxidation states are a key property of transition elements and distinguish them from most other metals.
CuSO4 solution is ______ in colour, showing that copper forms ______ compounds.
CuSO4 solution is blue in colour, showing that copper forms coloured compounds.
Why are transition elements widely used as industrial catalysts?
Transition elements are effective catalysts because they can form ions with variable oxidation states, allowing them to accept and donate electrons during a reaction.
Why are scandium and zinc not classed as transition elements, despite being in the transition element region of the table?
Scandium and zinc are not classed as transition elements because they do not form coloured compounds and each has only one oxidation state.
Why are the noble gases described as inert?
Noble gases are inert because they have full outer shells of electrons, making their electronic configurations extremely stable and leaving no tendency to gain or lose electrons.
Helium has the electronic configuration ______ and neon has the configuration ______, both giving a full outer shell.
Helium has the electronic configuration 2 and neon has the configuration 2,8, both giving a full outer shell.
True or False?
Noble gases are diatomic molecules.
False.
Noble gases are monoatomic, meaning each particle consists of a single atom.
Why do noble gases not form bonds with other elements?
Noble gases do not form bonds because their outer shells are already full, so they have no need to gain or lose electrons to achieve stability.
The noble gases are located in Group ______ of the Periodic Table and are all ______ at room temperature.
The noble gases are located in Group VIII of the Periodic Table and are all gaseous at room temperature.
How many electrons does argon have in its outer shell, and how does this explain its lack of reactivity?
Argon has 8 electrons in its outer shell. This full outer shell means argon has no tendency to gain or lose electrons, so it does not react.
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