Fig. 1 is part of a safety poster for a laboratory that stores gases in sealed cylinders. The poster compares chlorine with argon. Chlorine is used to disin...
Question 1 Report
Fig. 1 is part of a safety poster for a laboratory that stores gases in sealed cylinders. The poster compares chlorine with argon. Chlorine is used to disinfect water, while argon is used to protect hot metal during welding. Both substances are elements, but their position in the periodic table is different.
(a) Name the group containing argon. [1]
(b) Describe the difference between the outer electron shells of chlorine and argon. [2]
(c) Explain why argon can protect hot metal from reacting with oxygen. [2]
Fig. 1 shows part of a periodic table display used in a museum. The coloured boxes have been replaced by letters so that visitors can focus on the pattern of the elements. Element R is a shiny solid which is stored under oil because it reacts quickly with water. Element T is a pale gas used in some lamps. The museum guide says that elements in the same vertical group have related chemical properties.
(a) Name the group containing R. [1]
(b) Use the information about R to explain why oil is placed above the metal. [2]
(c) What property makes T suitable for a lamp? [1]
Answer Details
Chlorine and argon
(a) Argon is in Group 0, the noble gases. [1]
(b) Chlorine has seven outer-shell electrons [1], whereas argon has a full outer shell, containing eight outer-shell electrons. [1]
(c) Argon is unreactive. [1] It does not react with hot metal and excludes oxygen from the metal surface, reducing oxidation. [1]
R and T in the periodic-table display
(a) R is in Group 1, the alkali metals. [1]
(b) Oil prevents water reaching the metal. [1] Therefore the vigorous reaction with water that produces hydrogen does not occur. [1]
(c) T is suitable for a lamp because it is unreactive, or chemically inert. [1]
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