Question

Group 1B(11) elements (see the periodic table on the inside cover of your book) have one electron in their outer energy level, as do Group \(1 \mathrm{~A}(1)\) elements. Would you expect them to form compounds such as \(\mathrm{CuCl}, \mathrm{AgCl}\), and \(\mathrm{AuCl}\) ? Explain.

Short answer

Given that Group 1B(11) elements have a single electron in their outer energy level, they can indeed form compounds such as CuCl, AgCl, and AuCl by donating this electron to form +1 cations.

Step-by-step solution

Understanding the Electron Configuration

Examine the electron configuration of Group 1B(11) elements, which includes copper (Cu), silver (Ag), and gold (Au). Recognize that these elements have one electron in their outermost energy level, similar to the alkali metals in Group 1A(1).

Comparing Chemical Reactivity

Consider the chemical reactivity of Group 1B(11) elements compared to Group 1A(1) elements. Both groups have one electron available for bonding in their outer shell, suggesting a valence of +1 when forming compounds.

Predicting Compound Formation

Predict the likelihood of Group 1B(11) elements forming compounds like CuCl, AgCl, and AuCl. Since these elements can lose one electron to achieve a stable electronic configuration, they can form +1 ionic compounds with anions like Cl-.

Considering Other Factors

Acknowledge other factors affecting compound formation, such as electronegativity, ionization energy, and the overall energy change during the formation of the compound. These factors influence the stability of the resulting compounds.

Key concepts

Electron Configuration of Group 1B Elements

Group 1B(11) elements, specifically copper (Cu), silver (Ag), and gold (Au), are unique in their electron configuration. While they belong to the d-block of the periodic table, they possess one electron in their outermost energy level, akin to the s-block's Group 1A(1) alkali metals. This distinctive configuration arises because the energy levels of the outer s and d-orbitals are very close, allowing for a single electron to occupy the s-orbital despite these elements being transition metals. For instance, the electron configuration of silver (Ag) ends as [Kr]4d^105s^1, indicating that the most accessible electron for chemical bonding is in the outermost s-orbital.

Understanding this single electron's presence in the outer energy level is fundamental to comprehending the chemical behavior of these metals, because it is this electron that is involved in bond formation.

Chemical Reactivity of Group 1B Elements

The similarity in the outer electron structure between Group 1B(11) and Group 1A(1) elements might lead to an assumption that they share similar chemical reactivities. However, that's not entirely the case. Although both groups have one electron in their outer shell, the chemical reactivity of Group 1B elements is generally less than that of the alkali metals in Group 1A. The reason lies in their metallic character and the effective nuclear charge they experience. Group 1B elements are transition metals; thus, they have a partially filled d-subshell which influences their ability to lose electrons.

The greater nuclear charge and the shielding effect of the d-electrons make it more challenging for these elements to ionize compared to Group 1A elements. This results in higher ionization energies and electrodes with more modest reactivity patterns. Their valence electron is not as loosely held, which impacts their participation in chemical reactions including bond formation in compounds such as CuCl, AgCl, and AuCl.

Ionic Compound Formation

Predicting the formation of ionic compounds such as CuCl, AgCl, and AuCl involves considering the ability of Group 1B(11) elements to lose their single valence electron and form cations. The electron from the outermost energy level can be donated to a non-metal like chlorine, resulting in an ionic bond.

The resulting compounds, where Group 1B elements adopt a +1 oxidation state, are ionic in nature. However, the extent of ionic character varies due to factors such as lattice energy and the specific properties of the involved ions. Because the Group 1B elements are less reactive than alkali metals, the resulting ionic compounds might be less stable compared to those formed by Group 1A elements. Nonetheless, compounds such as AgCl are well-documented, highlighting the propensity of silver to form a stable +1 ion.

Understanding Valence Electrons

Valence electrons play a critical role in the chemistry of an element because they are the electrons available for bonding. In Group 1B(11) elements, this refers to the single electron located in the outermost energy level. These electrons determine how an element will bond with others.

While Group 1B elements have just one valence electron, like Group 1A, the former's valence electron is located in an s-orbital following a complete d-orbital. This subtle difference affects the way these elements participate in chemical bonds. When Group 1B elements form bonds by losing their valence electron, they achieve a noble gas configuration which is energetically favorable. However, due to the higher ionization energies and lower reactivity compared to Group 1A, the resulting compounds exhibit unique chemical and physical properties related to their valence electron structures.