Question

When two atoms share two pairs of electrons, a(n)_____ bond is said to exist between them.

Short answer

When two atoms share two pairs of electrons, a(n) \(\text{double covalent}\) bond is said to exist between them.

Step-by-step solution

Identify the Types of Chemical Bonds

There are various types of chemical bonds, including ionic, covalent, and metallic bonds. In this exercise, we are looking for a bond between two atoms involving the sharing of electrons. This indicates that we are dealing with a covalent bond.

Covalent Bond Categories

Covalent bonds involve the sharing of one or more pairs of electrons between two atoms. They can be categorized based on the number of electron pairs being shared: 1. Single covalent bond: shares one pair of electrons 2. Double covalent bond: shares two pairs of electrons 3. Triple covalent bond: shares three pairs of electrons

Identify the Type of Bond

The exercise states that two atoms share two pairs of electrons, which corresponds to a double covalent bond. So, the answer is: When two atoms share two pairs of electrons, a(n) _double covalent_ bond is said to exist between them.

Key concepts

Double Covalent Bond

In chemistry, the way atoms bond together is key to understanding the properties of different substances. A double covalent bond involves two atoms sharing two pairs of electrons. This is a stronger bond than a single covalent bond, where only one pair of electrons is shared. The double bond contributes to the stability and the physical characteristics of the compound it forms.

For instance, the oxygen we breathe has two oxygen atoms joined by a double covalent bond. This double bond is represented in chemical structures by two parallel lines between the atoms (O=O). Molecules with double bonds can show unique behaviors, such as being more reactive or having the ability to absorb light at different wavelengths, leading to coloration in some compounds.

When drawing Lewis structures, which represent the valence electrons in a molecule, double covalent bonds are essential for depicting molecules with a full octet, satisfying the atoms' needs for a stable electron arrangement.

Chemical Bonds

Atoms form chemical bonds to achieve greater stability, often by acquiring a noble gas electron configuration. Three primary types of chemical bonds exist: ionic, covalent, and metallic.

• Ionic bonds occur when electrons are transferred from one atom to another, resulting in oppositely charged ions that attract each other.
• Covalent bonds, including single, double, and triple bonds, involve the sharing of electron pairs between atoms.
• Metallic bonds are found in metal elements where electrons move freely among a lattice of metal cations.

Understanding these bonding types is fundamental to predicting the properties of a substance, such as melting and boiling points, electrical conductivity, and solubility.

Electron Sharing

Electron sharing is at the heart of covalent bonding and is a key concept in understanding molecular structures and reactions. Atoms share electrons to fill their outermost electron shells, achieving a more stable electron configuration. This mutual sharing allows for the formation of molecules with specific geometries that determine the physical and chemical properties of the substance.

In electron sharing, the number of shared electrons determines the bond type: one pair for a single bond, two pairs for a double bond, and three pairs for a triple bond. Through this sharing, atoms attain the 'octet rule', where an atom is most stable when it has eight electrons in its valence shell. However, there are exceptions to this rule, such as hydrogen, which aims for a 'duet', having only two electrons in its outer shell. These nuances of electron sharing are crucial for predicting the behavior and reactivity of different molecules in chemical reactions.