Question

In Table 7.8 , the bonding atomic radius of neon is listed as 0.58 A, whereas that for xenon is listed as 1.40 A. A classmate of yours states that the value for Xe is more realistic than the one for Ne. Is she correct? If so, what is the basis for her statement?

Short answer

The classmate's statement that the value for Xe is more realistic than the one for Ne can be considered accurate, as xenon has more electron shells and stronger van der Waals forces compared to neon. These factors explain why xenon has a larger bonding atomic radius (1.40 Å) than neon (0.58 Å). However, it is essential to note that both values are relative and could be valid in the appropriate contexts, as they are usually experimentally determined or theoretically estimated using computational methods.

Step-by-step solution

Understand what bonding atomic radius is

Bonding atomic radius represents half the distance between two atoms that are chemically bonded together. It's a measure of the size of an atom in a chemical bond. For noble gases like neon and xenon, the bonding atomic radius mainly depends on their electron configurations and the van der Waals forces between gas atoms.

Analyze the electron configurations of Ne and Xe

Noble gases have full electron shells, which makes them stable and less reactive. We can analyze the electron configurations of neon (Ne) and xenon (Xe) to understand their atomic sizes. The electron configurations are: Neon (Ne): 1s² 2s² 2p⁶ Xenon (Xe): 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ As we go down the noble gas group in the periodic table, the atomic number increases, and more electron shells are present with filled orbits. Xenon has more electron shells than neon, which would mean Xe is expected to have a larger atomic size compared to Ne.

Examine van der Waals forces

Van der Waals forces are weak intermolecular forces present between noble gas atoms due to temporary dipoles created by the movement of electrons. As the size of noble gas atoms increases down the group (from Ne to Xe), the van der Waals forces generally get stronger. This would result in potentially larger distances between larger gas atoms when bonded.

Evaluate the statement based on properties of Ne and Xe

Considering the electron configurations and van der Waals forces, it's reasonable to expect that xenon (Xe) would have a larger bonding atomic radius than neon (Ne). The given values (Xe 1.40 Å and Ne 0.58 Å) are consistent with this expectation. Therefore, the classmate's statement that the value for Xe is more realistic than the one for Ne could be considered accurate. However, it is essential to note that both values are relative and could be valid in the appropriate contexts, as they are usually experimentally determined or theoretically estimated using computational methods.

Key concepts

Noble Gases

Noble gases, the last group in the Periodic Table, hold a unique place in chemistry due to their complete outer electron shells. These elements include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). As we move down the group, each noble gas has an additional electron shell compared to the one above it.

Because their outermost shell is full, noble gases are chemically inert, meaning they don’t react easily with other elements. This lack of reactivity gives them their 'noble' status, since they don’t readily form compounds. The completed shells also contribute to the atomic radius. As new shells are added with each step down the group, the atomic radius naturally increases. This is visible when comparing the bonding atomic radius of neon and xenon; neon has fewer electron shells than xenon, resulting in a smaller atomic radius.

Electron Configurations

Electron configurations are a shorthand way of illustrating the locations of electrons within an atom's electron shells and subshells. The configuration reflects the atom’s quantum mechanical properties and helps predict chemical behavior. For instance, a neon atom has the electron configuration of 1s² 2s² 2p⁶, signifying that its first and second electron shells are completely filled. This configuration confers stability to the atom.

Xenon, on the other hand, has a much more complex electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶. Each 'p⁶' sequence indicates a full p subshell, contributing to the element’s stability. Xenon's larger number of electron shells means that its electrons are further from the nucleus, compared to neon, increasing its atomic size. Understanding the electron configurations of noble gases is essential when considering properties like atomic radius and reactivity.

Van der Waals Forces

Van der Waals forces are the weak, attractive forces that occur between molecules or parts of molecules. These forces come into play due to fluctuations in electron density, which create temporary dipoles within atoms or molecules. Even though noble gases are nonreactive, van der Waals forces do exist between them and can influence their physical properties.

In noble gases, larger atoms like xenon have more electrons that can move around, creating stronger temporary dipoles compared to smaller atoms like neon. This results in stronger van der Waals forces in xenon, potentially increasing the distance between atoms when they are close to one another. While these forces are weak compared to chemical bonds, they are significant enough to affect states of matter and boiling points. A solid understanding of van der Waals forces is key for interpreting the behavior of non-polar substances and the noble gases in various conditions.