Question

How many electrons will be in the valence shell of \(\mathrm{H}\) atoms when it makes a covalent bond?

Short answer

Hydrogen will have 2 electrons in its valence shell when it forms a covalent bond.

Step-by-step solution

Understanding Valence Electrons

Hydrogen atoms have only one electron since their atomic number is 1. This electron resides in the first energy level, which is also the valence shell for hydrogen.

Valence Shell Capacity

The valence shell for hydrogen is its first energy level, which can hold a maximum of 2 electrons.

Covalent Bond Formation

In a covalent bond, hydrogen shares its electron with another atom. By sharing, it achieves a complete valence shell.

Number of Electrons in Valence Shell

When hydrogen forms a covalent bond, it shares one electron and gains another through sharing, resulting in 2 electrons in its valence shell.

Key concepts

Covalent Bond

A covalent bond is a type of chemical bond that occurs when two atoms share one or more pairs of electrons. This sharing allows each atom to attain the electron configuration of a noble gas, thereby achieving greater stability. Covalent bonds are typical in organic compounds and are often found between non-metal atoms.

These bonds can be either single, double, or triple bonds, depending on the number of electron pairs shared:

• Single Bond: Involves one pair of shared electrons (2 electrons).
• Double Bond: Involves two pairs of shared electrons (4 electrons).
• Triple Bond: Involves three pairs of shared electrons (6 electrons).

A single covalent bond is the simplest covalent bond and is crucial for many elements, including hydrogen, allowing them to achieve a filled valence shell.

Electron Sharing

Electron sharing is the fundamental mechanism behind covalent bonds. It involves atoms sharing their valence electrons to fill up their outer energy levels or valence shells. By doing this, each participating atom can achieve a more stable electron configuration.

For instance, when two hydrogen atoms form a covalent bond, each hydrogen atom shares its single electron. This results in both hydrogen atoms having access to two electrons, filling their outer shell to comply with the helium-like electron arrangement. By sharing, they satisfy the 'duet rule', a specific form of the 'octet rule' applicable to hydrogen and helium.

Electron sharing is not limited to two hydrogen atoms; it can occur between different atoms. Nevertheless, the principle remains the same—electrons are shared to fulfill stability needs. This electron sharing makes covalent compounds quite stable and allows them to form a variety of molecular shapes.

Hydrogen Atom

A hydrogen atom is the simplest atom and consists of only one proton and one electron. Because its atomic number is 1, hydrogen has a very basic electron configuration with just one electron that resides in its only energy level, also known as the valence shell.

In chemical reactions, hydrogen often participates by forming covalent bonds to complete its valence shell. Since its shell can hold up to two electrons, hydrogen seeks to achieve a stable configuration through sharing electrons with another atom.

Due to its simplicity and versatility, hydrogen is prevalent in numerous chemical compounds, including water (H extsubscript{2}O) and organic molecules like methanol (CH extsubscript{3}OH). It serves as a foundational building block for more complex molecules, enabling a variety of reactions and interactions in both organic and inorganic chemistry.