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A student is given samples of three elements, X, Y, and Z, which could be an alkali metal, a member of Group 4A, and a member of Group 5A. She makes the following observations: Element X has a metallic luster and conducts electricity. It reacts slowly with hydrochloric acid to produce hydrogen gas. Element Y is a light-yellow solid that does not conduct electricity. Element Z has a metallic luster and conducts electricity. When exposed to air, it slowly forms a white powder. A solution of the white powder in water is basic. What can you conclude about the elements from these observations?
Chapter 8, Problem 8.106(choose chapter or problem)
Questions & Answers
QUESTION: A student is given samples of three elements, X, Y, and Z, which could be an alkali metal, a member of Group 4A, and a member of Group 5A. She makes the following observations: Element X has a metallic luster and conducts electricity. It reacts slowly with hydrochloric acid to produce hydrogen gas. Element Y is a light-yellow solid that does not conduct electricity. Element Z has a metallic luster and conducts electricity. When exposed to air, it slowly forms a white powder. A solution of the white powder in water is basic. What can you conclude about the elements from these observations?
ANSWER:Element X:
Characters:
a. Metallic luster
b. Conducts electricity
c. It can produce gaseous hydrogen by slowly reacting with HCl.
These characteristics are consistent with the properties of alkali metals. Among the alkali metals, the element that most closely fits the given observations is Potassium (K).
Therefore, it is likely that Element X is Potassium (K).
Element Y:
Characters:
a. Light-yellow solid