Chapter 7: Problem 105
A student is given samples of three elements, \(X, Y,\) and \(\mathrm{Z}\), which could be an alkali metal, a member of Group 4A, or a member of Group 5A. She makes the following observations: Element \(\mathrm{X}\) 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?
Short Answer
Expert verified
Element X is an alkali metal, Element Y is from Group 5A, and Element Z is an alkali metal.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Alkali Metals
Alkali metals are fascinating elements prominently featured in Group 1 of the periodic table. These elements include lithium, sodium, and potassium, among others. They are known for their shiny appearance, which is often described as a metallic luster. This distinct trait makes them easily recognizable.
Another hallmark of alkali metals is their ability to conduct electricity efficiently. This property arises due to the free electrons in their outer shell, which allows electrical currents to pass through them with ease.
One of the defining characteristics of alkali metals is their reactivity with substances like hydrochloric acid. When they come into contact with acids, they react to produce hydrogen gas, an indicator of their high reactivity. Furthermore, when these metals react with water, they form basic solutions, sometimes even vigorously if conditions allow.
Alkali metals are quite reactive due to having only one electron in their outermost shell, making them eager to lose that electron in chemical reactions. This eagerness plays into a range of reactions, not just with acids but also with oxygen, forming oxides that often dissolve to create basic solutions.
Another hallmark of alkali metals is their ability to conduct electricity efficiently. This property arises due to the free electrons in their outer shell, which allows electrical currents to pass through them with ease.
One of the defining characteristics of alkali metals is their reactivity with substances like hydrochloric acid. When they come into contact with acids, they react to produce hydrogen gas, an indicator of their high reactivity. Furthermore, when these metals react with water, they form basic solutions, sometimes even vigorously if conditions allow.
Alkali metals are quite reactive due to having only one electron in their outermost shell, making them eager to lose that electron in chemical reactions. This eagerness plays into a range of reactions, not just with acids but also with oxygen, forming oxides that often dissolve to create basic solutions.
Group 4A Elements
Group 4A of the periodic table showcases a fascinating mix of elements, each with unique properties. This group includes carbon, silicon, tin, and lead. Unlike alkali metals, elements from Group 4A exhibit a wide variety of characteristics, from nonmetals to metalloids and metals.
Typically, non-metallic elements in this group, like carbon, do not form basic solutions when dissolved in water. Metals found in this group, such as tin and lead, are generally less reactive than alkali metals. Silicon, a metalloid, shares properties between metals and nonmetals. Its oxide, silicon dioxide, is a familiar component in materials like sand.
The reactivity of Group 4A elements is generally less dramatic compared to Group 1. Oxidation reactions can occur, but these are not characterized by the vigorous reactivity seen in alkali metals. As a result, basic solutions from such reactions are rarely encountered.
Typically, non-metallic elements in this group, like carbon, do not form basic solutions when dissolved in water. Metals found in this group, such as tin and lead, are generally less reactive than alkali metals. Silicon, a metalloid, shares properties between metals and nonmetals. Its oxide, silicon dioxide, is a familiar component in materials like sand.
The reactivity of Group 4A elements is generally less dramatic compared to Group 1. Oxidation reactions can occur, but these are not characterized by the vigorous reactivity seen in alkali metals. As a result, basic solutions from such reactions are rarely encountered.
Group 5A Elements
The periodic table's Group 5A hosts another set of intriguing elements, which include a mix of nonmetals, metalloids, and metals. Prominent members of this group are nitrogen, phosphorus, arsenic, and, notably for this discussion, sulfur.
Group 5A elements often present as non-metals and are characterized by their lack of metallic luster. They generally do not conduct electricity, as seen with sulfur, which is typically a light yellow solid. The electrical insulating properties are due to the structure of these elements, which lack the free electrons needed for conduction.
Unlike alkali metals, Group 5A elements like sulfur do not react quickly with hydrochloric acid or water. Reactions tend to be slower and less pronounced. The solid state at room temperature is another notable trait, often presenting vibrant colors such as yellow, common in sulfur.
Group 5A elements often present as non-metals and are characterized by their lack of metallic luster. They generally do not conduct electricity, as seen with sulfur, which is typically a light yellow solid. The electrical insulating properties are due to the structure of these elements, which lack the free electrons needed for conduction.
Unlike alkali metals, Group 5A elements like sulfur do not react quickly with hydrochloric acid or water. Reactions tend to be slower and less pronounced. The solid state at room temperature is another notable trait, often presenting vibrant colors such as yellow, common in sulfur.
Chemical Reactions
Chemical reactions are processes where substances, known as reactants, are transformed into different substances, called products. The changes happen through rearrangement of atoms, which involves breaking and forming bonds.
For elements like alkali metals, chemical reactions can happen quite readily. These metals react with acids to release hydrogen gas and with oxygen in the air to form oxides. These oxides can further dissolve in water to create hydroxides, known for being basic in nature.
Group 4A and 5A elements are less reactive than alkali metals. For instance, sulfur from Group 5A reacts slowly and less violently with its environment, compared to metals. Nonetheless, every element has the potential to engage in chemical reactions under the right conditions, which define the unique chemistry of each element.
For elements like alkali metals, chemical reactions can happen quite readily. These metals react with acids to release hydrogen gas and with oxygen in the air to form oxides. These oxides can further dissolve in water to create hydroxides, known for being basic in nature.
Group 4A and 5A elements are less reactive than alkali metals. For instance, sulfur from Group 5A reacts slowly and less violently with its environment, compared to metals. Nonetheless, every element has the potential to engage in chemical reactions under the right conditions, which define the unique chemistry of each element.
Metallic Properties
Metallic properties stem from certain characteristics like luster, conductivity, malleability, and ductility. Metals are typically noted for their shiny surface, which is often due to their ability to reflect light.
Electrical conductivity is another major metallic property. Metals have free-moving electrons that allow electricity to flow, making them excellent conductors. This property is one of the reasons metals are so widely used in wiring and electronic devices.
Metals can react with their environments in various ways. For example, the reaction of a metal with oxygen can lead to the formation of oxides. These oxides may possess different properties compared to the original metal. When a metal reacts with water, the solution formed can be basic, especially in the case of alkali metals, indicating their high level of reactivity.
Electrical conductivity is another major metallic property. Metals have free-moving electrons that allow electricity to flow, making them excellent conductors. This property is one of the reasons metals are so widely used in wiring and electronic devices.
Metals can react with their environments in various ways. For example, the reaction of a metal with oxygen can lead to the formation of oxides. These oxides may possess different properties compared to the original metal. When a metal reacts with water, the solution formed can be basic, especially in the case of alkali metals, indicating their high level of reactivity.
