3. Use the periodic table to help you answer the following question - Edexcel - GCSE Chemistry - Question 3 - 2017 - Paper 1
Question 3
3. Use the periodic table to help you answer the following question.
Which of these metals will form coloured cations?
Put a cross (✗) in the box next to your answer... show full transcript
Worked Solution & Example Answer:3. Use the periodic table to help you answer the following question - Edexcel - GCSE Chemistry - Question 3 - 2017 - Paper 1
Step 1
Which of these metals will form coloured cations?
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The metals that form coloured cations are generally transition metals. In this case, a cross (✗) should be placed next to 'Chromium, Cr' (B). Gallium, Strontium, and Sodium typically form colourless cations.
Step 2
Explain, in terms of the structure of their atoms, why caesium is more reactive than lithium.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Caesium is more reactive than lithium because it has a larger atomic size. As you move down Group 1 in the periodic table, atomic size increases due to the addition of electron shells. This makes it easier for caesium to lose its outermost electron, as it is further away from the nucleus and experiences less electrostatic attraction, thereby enhancing its reactivity.
Step 3
Write the balanced equation for this reaction.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The balanced equation for the reaction of potassium with water is:
2K+2H2O→2KOH+H2
This shows that potassium reacts vigorously with water to form potassium hydroxide and hydrogen gas.
Step 4
Which of these is the balanced equation for this reaction?
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The balanced equation is option C:
Cl2+2KBr→2KCl+Br2
This indicates that chlorine reacts with potassium bromide to produce potassium chloride and bromine.
Step 5
Explain why filament light bulbs were filled with argon rather than left with air inside them.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Filament light bulbs were filled with argon instead of air to prevent the filament from oxidizing at high temperatures. Argon is an inert gas that does not react with the hot filament, thereby prolonging the life of the bulb. In contrast, the oxygen in air would react with the filament, leading to rapid deterioration and failure.
