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DSE Chemistry: Patterns in the Chemical World — Practice Questions & Answers
Periodic trends across periods and down groups, the characteristic chemistry of transition metals, and the consolidation of stoichiometry and chemical calculations.
102 practice questions available for this topic — here are 10 with full answers and explanations.
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Practice questions with answers
1
Multiple choice · Medium
Which is NOT a characteristic property of transition metals?
They react with dilute hydrochloric acid to give hydrogen gas
They form coloured compounds
They exhibit variable oxidation numbers
They show catalytic properties as elements or compounds
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Why Transition metals are generally unreactive; reacting with dilute HCl to give hydrogen is not characteristic of them.
2
Multiple choice · Easy
Which observation suggests an element is a transition metal?
its compounds are coloured
its compounds are always white
it has a very low melting point
it is a gas at room temperature
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Why Coloured compounds are typical of transition metals.
3
Multiple choice · Hard
Manganese exists as +2, +4 and +7 in different compounds. This best illustrates that transition metals have
variable oxidation numbers
only one fixed valency
no catalytic activity
low densities
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Why Several oxidation numbers indicate variable oxidation states.
4
Fill in the blank · Easy
Transition metals often form
Check answer
Answer:
coloured / colored
Why They form coloured compounds.
5
Fill in the blank · Medium
In manganese(IV) oxide, MnO2, the oxidation number of manganese is
Check answer
Answer:
+4 / 4
Why Each O is -2, so Mn is +4.
6
Fill in the blank · Medium
Transition metals and their compounds are widely used as
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Answer:
catalysts / catalyst
Why They act as catalysts.
7
Multiple choice · Medium
In Group I, reactivity with chlorine:
Increases from Na to Cs
Decreases from Na to Cs
Is the same for all
Is highest for Na
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Why Reactivity increases from sodium down to caesium.
8
Multiple choice · Medium
The general equation for an alkali metal M reacting with chlorine is:
2M + Cl2 -> 2MCl
M + Cl2 -> MCl2
2M + Cl -> 2MCl
M + Cl -> MCl
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Why Two M atoms react with one Cl2 to give 2MCl.
9
Multiple choice · Medium
Caesium reacts more vigorously than sodium because caesium loses its outer electron:
More easily
Less easily
By sharing
By gaining electrons
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Why The larger atom loses its outer electron more easily.
10
Fill in the blank · Medium
Group I metals are stored under
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Answer:
oil / paraffin oil
Why They are stored under oil.
Key terms in Patterns in the Chemical World
Periodic table: An arrangement of elements in order of increasing atomic number showing periodic patterns.
Periodicity: The repeating pattern in properties of elements as atomic number increases.
Periodic trend: A regular change in a property such as atomic size across a period or down a group.
Atomic radius: A measure of the size of an atom, which decreases across a period and increases down a group.
Alkali metal: A reactive Group I metal with one valence electron that forms a singly charged positive ion.
Halogen: A reactive Group VII non-metal with seven valence electrons that forms a singly charged negative ion.
Noble gas: A Group 0 element with a full outer shell that is very unreactive.
Transition metal: A d-block metal showing variable oxidation states, coloured compounds and catalytic activity.
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