Question

Valence Bond Theory The valence electron configurations of several atoms are shown below. How many bonds can each atom make without hybridization? $$\quad \text { a. } \mathrm{B} 2 \mathrm{s}^{2} 2 p^{1} \quad \text { b. } \mathrm{N} 2 \mathrm{s}^{2} 2 \mathrm{p}^{3} \quad \text { c. } \mathrm{O} 2 \mathrm{s}^{2} 2 \mathrm{p}^{4}$$

Short answer

Boron can form 1 bond, Nitrogen can form 3 bonds, and Oxygen can form 2 bonds without hybridization.

Step-by-step solution

Identifying Valence Electrons for Boron

Examine the given electronic configuration for boron (B), which is \(2s^{2}2p^{1}\). Boron has three valence electrons in total: two in the \(2s\) orbital and one in the \(2p\) orbital.

Determining Bonding Capacity for Boron

Since boron has one unpaired electron in the \(2p\) orbital, it can form one bond without hybridization. The \(2s\) electrons, as a filled subshell, do not usually participate in bonding without hybridization.

Identifying Valence Electrons for Nitrogen

Inspect the electronic configuration for nitrogen (N), which is \(2s^{2}2p^{3}\). Nitrogen has five valence electrons: two in the \(2s\) orbital and three in the \(2p\) orbital.

Determining Bonding Capacity for Nitrogen

There are three unpaired electrons in the \(2p\) orbital, which allows Nitrogen to form three bonds without hybridization.

Identifying Valence Electrons for Oxygen

Look at the electronic configuration for oxygen (O), which is \(2s^{2}2p^{4}\). Oxygen has six valence electrons: two in the \(2s\) orbital and four in the \(2p\) orbitals.

Determining Bonding Capacity for Oxygen

With four electrons in the \(2p\) orbital, there are two unpaired electrons, allowing oxygen to form two bonds without hybridization.

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom and are crucial in determining how an element will react with others to form chemical bonds. They are located in the outermost energy level, or shell, of an atom and can be involved in the formation of covalent bonds where electrons are shared between atoms.

In our exercise, we look at Boron (B), which has a configuration of 2s^{2}2p^{1}, indicating that it has three valence electrons. These are the electrons that can participate in bonding. Nitrogen (N), with a configuration of 2s^{2}2p^{3}, has five valence electrons. Lastly, Oxygen (O), has a configuration of 2s^{2}2p^{4}, revealing six valence electrons.

The filling of these outer shells, particularly the orbital types such as 's' and 'p', can affect the reactivity and bonding patterns of an element.

Atomic Bonding Capacity

The bonding capacity, or the number of chemical bonds an atom can form, is determined by the number of unpaired valence electrons. If an atom has unpaired electrons, it can form a bond by pairing up with unpaired electrons from another atom. Elements will bond with other atoms to achieve a noble gas electron configuration. This is often referred to as the octet rule, which states that atoms tend to form bonds in such a way that they each have eight electrons in their valence shells, giving them the same electronic configuration as a noble gas.

For example, Boron has one unpaired electron and thus can form one bond. Nitrogen, with three unpaired electrons, is typically capable of forming three bonds. Oxygen, which has two unpaired electrons, can commonly form two bonds. The bond capacity is a vital aspect of understanding molecular structure and bonding patterns.

Electronic Configuration

The electronic configuration of an atom describes the distribution of electrons in the atom's orbits or shells and subshells. It follows a set of principles, such as the Aufbau principle, which says that electrons fill lower-energy orbitals before occupying higher-energy ones, and Hund's rule, which states that electrons will occupy degenerate orbitals singly before filling them in pairs.

An atom like Boron, with the electron configuration of 2s^{2}2p^{1}, follows these rules with electrons first filling the lower energy 2s orbital and then starting to fill the higher energy 2p orbital. It's this arrangement that affects the atom's valence and bonding properties. Being familiar with an atom's electronic configuration is key to predicting its chemical behavior, as this determines the valence electron structure and, consequently, its bonding characteristics.