Table 10.1 gives some information about the elements in Group VII. Table 10.1 Element Proton number Colour State at room temperature fluorine 9 pale yellow ...
Question 1 Report
Table 10.1 gives some information about the elements in Group VII.
| Element | Proton number | Colour | State at room temperature |
|---|---|---|---|
| fluorine | 9 | pale yellow | gas |
| chlorine | 17 | gas | |
| bromine | 35 | red-brown | |
| iodine | 53 |
(a) Complete Table 10.1 by filling in the four empty boxes. [4]
(b) State the trend in melting point going down the group. [1]
(c) State the trend in colour going down the group. [1]
(d) Astatine is below iodine in the group. Predict the physical state of astatine at room temperature. [1]
(e) The elements exist as diatomic molecules. State what is meant by the term diatomic. [1]
(f) State the trend in reactivity going down the group. [1]
(g) Name the most reactive element in the group shown in Table 10.1. [1]
(h) Give the formula of a molecule of chlorine. [1]
Answer Details
This question tests the trends in colour, state and reactivity down Group VII. Down the group the elements get darker, their melting and boiling points rise (so the state goes gas to liquid to solid) and reactivity decreases.
(a) The four empty boxes, using the trends, are filled as follows [4] (one mark each):
| Element | Proton number | Colour | State at room temperature |
|---|---|---|---|
| fluorine | 9 | pale yellow | gas |
| chlorine | 17 | pale green / yellow-green | gas |
| bromine | 35 | red-brown | liquid |
| iodine | 53 | grey-black / dark grey | solid |
Chlorine colour = pale green [1]; bromine state = liquid [1]; iodine colour = grey-black [1]; iodine state = solid [1].
(b) Melting point increases going down the group [1].
(c) The colour gets darker going down the group [1] (pale yellow to green to red-brown to grey-black).
(d) Astatine is below iodine, with even higher melting and boiling points, so it is a solid at room temperature [1].
(e) Diatomic means a molecule made of two atoms joined together [1], such as \( \text{Cl}_2 \).
(f) Reactivity decreases going down the group [1].
(g) The most reactive element shown is fluorine (highest in the group) [1].
(h) A molecule of chlorine is \( \text{Cl}_2 \) [1].
Exam tip: read the trends in one direction and every prediction follows; down Group VII means darker, higher melting/boiling points and less reactive.
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