Question

Give an example of a nonpolar covalent bond. How do you know it is nonpolar?

Short answer

H₂ is an example of a nonpolar covalent bond because the two hydrogen atoms share electrons equally.

Step-by-step solution

Understanding Covalent Bonds

Covalent bonds are formed when two atoms share pairs of electrons. In simple terms, they are the bonds that hold compounds together by sharing electrons between non-metal atoms. The strength and type of covalent bond are determined by how equally or unequally these electrons are shared between the atoms.

Identifying Nonpolar Covalent Bonds

A nonpolar covalent bond occurs when electrons are shared equally between two identical atoms. This happens because both atoms have the same electronegativity, meaning there is no difference in their desire to attract electrons. When there is no significant difference in electronegativity, the bond is nonpolar.

Selecting an Example

A good example of a nonpolar covalent bond is the bond between two hydrogen atoms in a hydrogen molecule (H₂). Here, two hydrogen atoms share their electrons equally because they have the same electronegativity value, which results in a nonpolar covalent bond.

Explaining the Nonpolarity of H₂

In a hydrogen molecule, each hydrogen atom contributes one electron, which forms a pair of electrons shared equally. Since both hydrogen atoms are identical with equal electronegativities, there is no net charge on either end of the molecule, thus making the bond nonpolar.

Key concepts

Covalent Bonds

Covalent bonds are a fundamental type of chemical bond. They occur when two atoms share electrons to achieve stability, usually forming between non-metal atoms. This sharing enables each atom to fill its outer electron shell, often completing it and reaching a more stable electronic arrangement similar to that of noble gases. Covalent bonds vary in strength depending on how equally the electrons are shared. The bond can be considered a strong force because the shared pair of electrons is attracted to the nuclei of both bonded atoms.
Some key characteristics of covalent bonds include:

• Involves sharing of electrons.
• Occurs typically between non-metal atoms.
• Forms molecules with distinct shapes.
• Can be single, double, or triple bonds depending on the number of shared electron pairs.

Understanding covalent bonds helps in grasping how different substances are formed and how their basic structures and properties relate to their chemical behavior.

Electronegativity

Electronegativity is a measure of how strongly an atom can attract and hold onto electrons in a bond. It is a crucial concept in understanding why certain covalent bonds are nonpolar, while others are polar. Electronegativity values vary across the periodic table, generally increasing from left to right and bottom to top. This is why elements such as fluorine have high electronegativity values, while elements like cesium have low values.
When two atoms have similar electronegativities, they tend to share electrons equally, forming nonpolar covalent bonds. Conversely, if there is a significant difference in electronegativity between two bonded atoms, the electrons are shared unequally, resulting in a polar covalent bond.
Key points about electronegativity:

• A high electronegativity means a strong attraction for electrons.
• Differences in electronegativity determine polarity of covalent bonds.
• The scale is relative, with fluorine having the highest known value.

Hydrogen Molecule

The hydrogen molecule, represented as H₂, is a simple yet classic example of a nonpolar covalent bond. It consists of two hydrogen atoms, each contributing one electron to form a pair. These two electrons are shared equally between the two atoms because hydrogen atoms have identical electronegativity.
This equal sharing means there is no charge difference across the molecule, thus it is considered nonpolar. As the simplest molecule, it serves as a foundational example in chemistry education to illustrate concepts of covalent bonding and electronegativity.
Key characteristics of the hydrogen molecule:

• It is the simplest molecule consisting of two identical atoms.
• Electrons are shared equally between the atoms, resulting in a nonpolar bond.
• Shows the concept of achieving stability by completing outer electron shells.

Understanding the hydrogen molecule helps students appreciate how molecules form and the significance of nonpolar covalent bonds in chemistry.