Let's address each question step by step.
Question 4(a):
Choose an element from the list below which best fits the description.
- [tex]\( \text{Sr} \)[/tex]
Solution:
Strontium ([tex]\( \text{Sr} \)[/tex]) is an element that reacts with cold water to form strontium hydroxide and hydrogen gas. The reaction can be represented by:
[tex]\[ \text{Sr} + 2\text{H}_2\text{O} \rightarrow \text{Sr(OH)}_2 + \text{H}_2 \][/tex]
Thus, the element that reacts with cold water is Strontium ([tex]\( \text{Sr} \)[/tex]).
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Question 4(b):
It is a solid at room temperature and exists as diatomic molecules [tex]\( \text{X}_2 \)[/tex].
Solution:
To identify an element that fits this description, let’s consider two aspects:
1. The element is a solid at room temperature.
2. The element exists in a diatomic form [tex]\( \text{X}_2 \)[/tex].
Given these properties, elements like iodine ([tex]\( \text{I}_2 \)[/tex]) fit the bill. Iodine is a solid at room temperature and exists as diatomic molecules. Therefore, the element is Iodine ([tex]\( \text{I}_2 \)[/tex]).
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Question 4(c):
The element can form two oxides, [tex]\( \text{XO} \)[/tex] and [tex]\( \text{X}_2\text{O}_3 \)[/tex].
Solution:
We need an element that can form two types of oxides [tex]\( \text{XO} \)[/tex] and [tex]\( \text{X}_2\text{O}_3 \)[/tex]. One such element is Aluminum ([tex]\( \text{Al} \)[/tex]):
- Aluminum Oxide ([tex]\( \text{Al}_2\text{O}_3 \)[/tex])
- Another form of oxide can be hypothetical or specific under certain oxidation states.
Thus, the element that can form these oxides is Aluminum ([tex]\( \text{Al} \)[/tex]).
