IGCSE Chemistry The Periodic Table topical questions

An element has the electronic configuration 2,8,1.

1. (a)Name the element.[1]
2. (b)State its group.[1]
3. (c)State its period.[1]

Samples of chlorine, bromine and iodine are kept in bottles on a bench at room temperature.

1. (a)Describe the appearance of chlorine.[1]
2. (b)Describe the appearance of iodine.[1]

Three elements have these electronic configurations: P is 2,7; Q is 2,8,2; R is 2,8,8.

1. (a)Identify which element is in Group VII.[1]
2. (b)Identify which element is a noble gas.[1]
3. (c)Write the formula of the ion formed by Q.[1]

Small pieces of lithium and potassium are dropped into separate beakers of cold water.

1. (a)Describe one observation that shows potassium reacts more vigorously than lithium.[2]
2. (b)Name the two products formed in each reaction.[2]

Aqueous chlorine is added to aqueous potassium iodide.

1. (a)State the colour change observed.[1]
2. (b)Write the ionic equation for the reaction.[2]
3. (c)Explain why the reaction occurs.[1]

Sodium and chlorine are neighbouring elements in period 3.

1. (a)Write the electronic configuration of sodium and of chlorine.[1]
2. (b)Write the formula of the ion that each element forms.[2]
3. (c)State how the acid–base character of the oxides of period 3 changes from sodium oxide to the oxides of sulfur.[1]

Aqueous bromine is added separately to aqueous potassium chloride and to aqueous potassium iodide.

1. (a)State what is observed in the potassium chloride solution.[1]
2. (b)State what is observed in the potassium iodide solution and name the product formed.[2]
3. (c)Write the ionic equation for the reaction that occurs in part (b).[1]

Astatine (At) is a Group VII element below iodine in the Periodic Table. Its relative molecular mass is about 420.

1. (a)Predict the physical state of astatine at room temperature and explain your prediction.[2]
2. (b)Predict whether astatine can displace chloride ions from aqueous potassium chloride. Explain your answer.[2]
3. (c)State how many atoms are in one molecule of astatine.[1]

The table gives information about two compounds of iron and one compound of copper.

1. (a)State one property of transition elements shown by the colours in the table.[1]
2. (b)Deduce the oxidation number of iron in FeCl₂ and in FeCl₃.[2]
3. (c)Name the property of transition elements that makes iron useful inside the Haber process reactor.[1]
4. (d)Suggest why copper, a transition element, is used for electrical wiring rather than for catalysis.[1]

Sodium and iron are both metals, yet they behave very differently in their compounds.

1. (a)Give two differences between the properties of sodium and iron as metals.[2]
2. (b)Deduce the oxidation number of iron in FeO and in Fe₂O₃. (Supplement)[2]
3. (c)Explain why Roman numerals are needed in the names of iron compounds but not in the name of sodium oxide.[1]