Question

Group 13 elements show (a) only \(+1\) oxidation state (b) only \(+3\) oxidation state (c) \(+1\) and \(+3\) oxidation states (d) \(+1,+2\) and \(+3\) oxidation states.

Short answer

Group 13 elements show both +1 and +3 oxidation states; therefore, the correct answer is (c) +1 and +3 oxidation states.

Step-by-step solution

Understanding Group 13 elements

Group 13 elements include Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), and Thallium (Tl). As you move down the group, the ability to show different oxidation states generally increases due to the inert pair effect.

Identifying Common Oxidation States

The most common oxidation state of Group 13 elements is +3. This is because the elements have three electrons in their outer shell which they can lose to form a stable cation. However, the heavier elements such as thallium can also display a +1 oxidation state due to the inert pair effect, where the two electrons in the s-orbital are not lost as easily.

Evaluating the Statement Options

By looking at the periodic trends and the oxidation states of group 13 elements, we can conclude that option (a) is incorrect, as not all Group 13 elements exhibit only the +1 oxidation state. Option (b) is partially true since all Group 13 elements can show a +3 oxidation state, but it is not the only one for all elements. Option (c) is correct, as both +1 and +3 oxidation states are shown by Group 13 elements, especially by thallium. Option (d) is incorrect because Group 13 elements do not commonly exhibit the +2 oxidation state.

Key concepts

Inert Pair Effect

The inert pair effect is an intriguing concept in chemistry that refers to the tendency of the two electrons in the s-orbital of the outermost energy level to resist participation in bonding as heavier elements are considered. This is particularly noticeable in the post-transition metals, including those in Group 13, like Indium (In) and Thallium (Tl).

As we move down Group 13 from Boron (B) to Thallium (Tl), the influence of these reluctant s-electrons becomes more significant. In simple terms, these s-orbital electrons are 'lazy' and prefer to remain non-bonding, or inert, which affects the oxidation states that the element can adopt. The inert pair effect explains why elements like thallium frequently have a stable +1 oxidation state, aside from the expected +3 state due to losing the p-orbital electrons alone.

Understanding the inert pair effect is crucial for predicting the behavior of heavy p-block elements and their compounds. It has practical implications in various fields such as material science, where the stability of oxidation states can influence the properties and uses of materials.

Oxidation States Chemistry

Oxidation states are a fundamental concept in chemistry that indicate the degree of oxidation of an atom within a compound. In the context of Group 13 elements, they can exhibit different oxidation states depending on various factors, including the inert pair effect. However, the most common oxidation state for Group 13 elements is +3.

For instance, boron (B) will almost always exhibit a +3 oxidation state because it readily loses its three valence electrons to achieve a noble gas configuration. Similarly, aluminum (Al) shows a predominant +3 oxidation state due to the same electron configuration reasoning. Nevertheless, when we consider elements like thallium (Tl), due to the inert pair effect, it can also comfortably exist in a +1 oxidation state by keeping its s-electrons paired and inert.

Oxidation states play a vital role in understanding redox reactions, compounds' formation, and the properties of elements. For students, mastering oxidation state chemistry is crucial for predicting reaction outcomes and grasping the underlying principles that define compound characteristics.

Periodic Trends

Periodic trends refer to the patterns and regularities that occur within the periodic table's elements as one progresses through the periods and groups. For Group 13 elements, these trends help explain variations in oxidation states, ionization energy, electronegativity, and the inert pair effect.

The increasing tendency to exhibit the +1 oxidation state in heavier Group 13 elements, as opposed to the universal +3 state, is a testament to the nuanced impact of periodic trends. The vertical changes within a group, such as increased atomic size and decreased electronegativity, contribute to the reduced ability of the s-electrons to engage in bonding as one moves from lighter to heavier elements within the group.

Students should recognize that periodic trends offer predictive power in chemistry. By understanding these trends, they can make educated guesses about an element's chemical behavior, such as reactivity and compound formation, and how these behaviors may change as one moves across or down the periodic table.