A student investigates an aqueous solution of an unknown potassium halide, KX\text{KX}KX:
Which of the following correctly describes the expected observation for the reaction with chlorine gas, and the correct trend and explanation for the electronegativity of the elements down Group 7?
An orange-brown solution is formed; electronegativity decreases down Group 7 because atomic radius and shielding increase.
A yellow-green solution is formed; electronegativity increases down Group 7 because the nuclear charge increases.
A dark-grey precipitate is formed; electronegativity decreases down Group 7 because the outer electrons are closer to the nucleus.
An orange-brown solution is formed; electronegativity increases down Group 7 because the electrostatic attraction to the bonding pair of electrons becomes stronger.
Practise Edexcel GCSE Chemistry Group 7 with exam-style questions for Foundation and Higher tier. 87 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.