CHEM001C_Chemical Bonding

Chemical Bond

• Attractive force between two atoms holding them together to form a molecule or a chemical compound.

• Forces that link together atoms to form different kinds of matter.

Valence Electrons

• Electrons located in the outermost energy level.

• Plays a crucial role in formation of chemical bonds.

Duet Rule

• states that hydrogen and helium may have no more than two electrons in their valence shells.

Octet Rule

• In forming chemical bonds, main group elements gain, lose , or share electrons to achieve configuration in which they are surrounded by eight valence electrons.

Ionic Bond

• there is an electron transfer between two atoms

• metal with non-metal

• the positively charged ion (cation) is attracted to negatively charged ion (anion).

• (Na-Cl, Ba-Cl, Na-O)

Covalent Bond

• formed by a shared pair of electrons between two atoms. 

• chemical bond formed when valence electrons are shared by nonmetal elements

• (CO, CO₂, CH₄)

Polar Covalent Bond

Type of chemical bond where a pair of electrons is unequally shared between two atoms.

Non-polar Covalent Bond

A bond that has an even distribution of charge due to an equal sharing of bonding electrons.

Types of Covalent Bonds

• due to difference in electronegativity of atoms

• if the electronegativity difference is zero, the bond is classified as nonpolar covalent

• the greater the electronegativity difference, the more polar the bond

• when the electronegativity difference greater than or equal to 2.0, the bond is classified as ionic

Metallic Bond

• "sea of electrons"

• Positively charged metal nuclei arranged in a lattice. 

• Electrons move, more or less, freely throughout the whole lattice.

• Free movement allows metals to conduct electricity

Single Bond

[TYPES OF BONDS] Two atoms share exactly one pair of electrons.

Double Bond

[TYPES OF BONDS] Consists of two pairs of shared electrons.

Triple Bond

[TYPES OF BONDS] Consists of three pairs of shared electrons.

Bond Length

• The distance between the nuclei of the bonded atoms.

• Single bond is longer than double bond, and double bond is longer than triple bond.

Bond Order

• The number of electron pairs shared between two atoms in the formation of the bond.

  • Single Bond:        Bond order = 1

  • Double Bond:     Bond order = 2

  • Triple Bond:         Bond order = 3

Bond Energy

• The energy released when isolated atoms form a covalent bond.

• The amount of energy required to break a bond (Bond dissociation energy).

• The larger the bond energy, the stronger the bond.

• Triple bond is stronger than double bond, and double bond is stronger than single bond.

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