8.1 The Periodic Table & Trends

The table below gives the electron distributions of atoms of different elements.

element electron distribution

For each of the following, select an element or elements from the table that matches the description.
Each element may be selected once, more than once or not at all.

These two elements are in the same group.

This element forms a fluoride with a formula of the type XF₃.

This element reacts violently with cold water.

Separate: Chemistry and Extended Only

This element has a macromolecular structure similar to that of diamond.

The only oxidation state of this element is 0.

This element is bromine.

This element is a good conductor of electricity.

Use your copy of the Periodic Table to help you answer some of these questions.

Predict the formulae of the following compounds.

Deduce the formulae of the following ions.

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Use the following ions to determine the formulae of the compounds.
          ions    OH^–    Cr³⁺    Ba²⁺    SO₄^2–

In the Periodic Table, the elements are arranged in columns called Groups and in rows called Periods.

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Across a period, the elements change from metallic to non-metallic.

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Separate: Chemistry Only

Trends can be observed in the way Group I and Group VII elements react. 

Suggest why Group I elements lithium, sodium and potassium are all stored in paraffin oil.

Separate: Chemistry and Extended Only

Caesium, Cs, is below potassium in Group I.

Separate: Chemistry Only

Table 5.1 gives some information about the halogens.

Complete the table by predicting the physical state of astatine at room temperature and the colour of astatine.

Table 5.1

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A student investigates the reactivity of some halogens.

She uses these solutions of halogens and their halides.

• bromine, chlorine and iodine
• sodium bromide, sodium chloride and sodium iodide

She adds each halogen solution to each halide solution.

Table 5.2 shows her results.

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Br₂ (aq) + 2I⁻ (aq) → I₂ (aq) + 2Br⁻ (aq)

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For each of the following, name an element which matches the description.

It is the only non-metal which is a good conductor of electricity.

Inert electrodes are made from this metal.

An element which can form an ion of the type X^3–.

It has the same electron distribution as the calcium ion, Ca²⁺.

The element is in Period 5 and Group VI.

Element Z is in Period 3 and Group V.

Identify element Z.

Helium, neon and argon are noble gases.

Explain, in terms of the electronic structure, why neon is unreactive.

Copper is a transition element. It can have variable oxidation states.

State two other chemical properties of transition elements which make them different from Group I elements.

Aqueous chlorine reacts with aqueous magnesium bromide.

How does this reaction show that chlorine is more reactive than bromine?

What colour is bromine in aqueous solution?

Complete the word equation to show the halogen and halide compound which react to form the products iodine and sodium chloride.

Explain, in terms of the reactivity of the halogens, why aqueous bromine will not react with aqueous sodium chloride.

The symbols of the elements in Period 2 of the Periodic Table are shown. 

Li  Be  B  C  N  O  F  Ne

For each of the following, give the symbol of an element from Period 2 which matches the description.

Each element may be used once, more than once or not at all.

Which element has atoms with only two electrons in the outer shell?

Which element is a monoatomic gas?

Which element is a soft metal stored in oil?

Which element has atoms with only seven protons?