Lewis Dot Structures and Molecular Geometry

Lewis Dot Structures

Diagrams showing valence electrons in atoms.

Valence Electrons

Electrons in the outermost shell of an atom.

Octet Rule

Atoms tend to have eight electrons in outer shell.

Hybridization

Mixing of atomic orbitals to form molecular orbitals.

Covalent Bond

Bond formed by sharing electrons between nonmetals.

Ionic Bond

Bond formed by transferring electrons from metal to nonmetal.

VSEPR Theory

Predicts molecular shapes based on electron repulsion.

Lone Pair

A pair of valence electrons not involved in bonding.

Electron Group

Regions of electron density around a central atom.

Central Atom

Atom in a molecule that other atoms bond to.

Symmetrical Arrangement

Even distribution of atoms around a central atom.

Bonding Pair

Two electrons shared between two atoms.

Formal Charge

Charge assigned to an atom in a molecule.

Electronegativity

Ability of an atom to attract electrons in a bond.

Molecular Geometry

3D arrangement of atoms in a molecule.

3D Shape

Spatial arrangement of atoms in a molecule.

Boron and Aluminum

Elements that can violate the Octet Rule.

Hydrogen Bonding

Hydrogen typically forms one bond only.

Row 2 Elements

Cannot exceed 8 electrons in their valence shell.

Row 3 Elements

Can exceed 8 electrons in their valence shell.

Electron Pair

Two electrons occupying the same orbital.

Lewis Dot Representation

Visual representation of valence electrons in atoms.

Negative Charge

Indicates an excess of electrons in an ion.

Positive Charge

Indicates a deficiency of electrons in an ion.

Molecular Polarity

Distribution of electrical charge across a molecule.

Single Bond

Bond formed by one pair of shared electrons.

Double Bond

Bond formed by two pairs of shared electrons.

Triple Bond

Bond formed by three pairs of shared electrons.

Electron Configuration

Distribution of electrons in an atom's orbitals.

Lewis Dot Structure

Diagram showing valence electrons and bonds.

Trigonal Planar

Three atoms bonded to central atom; 120° angles.

Bent Geometry

Two atoms and one lone pair; <120° angles.

Tetrahedral Geometry

Four atoms bonded to central atom; 109.5° angles.

Trigonal Pyramidal

Three atoms and one lone pair; <109.5° angles.

Bond Count

Each bond counts as two electrons.

Electron Ownership

Determined by counting shared and unshared electrons.

Molecular Orbitals

Regions around central atom where electrons reside.

Electron Geometry

Arrangement of electron pairs around central atom.

Oxygen Formal Charge

Calculated using valence electrons and bonds.

Bonding Electrons

Electrons involved in forming chemical bonds.

Non-bonded Electrons

Electrons not involved in bonding.

Hydrogen Exception

Hydrogen does not follow the octet rule.

Electron Counting

Count bonds and lone pairs for formal charge.

Geometry Determination

Based on electron pairs and bonded atoms.

Bond Angle

Angle between two adjacent bonds.

Molecular Shape

Describes arrangement of atoms in a molecule.

sp3 Hybridization

Four total orbitals with tetrahedral geometry.

Trigonal Bipyramidal

Five occupied orbitals around a central atom.

Seesaw Geometry

Four atoms and one lone pair in trigonal bipyramid.

T-shaped Geometry

Three atoms and two lone pairs in trigonal bipyramid.

Linear Geometry

Two atoms and three lone pairs around central atom.

Octahedral Geometry

Six occupied orbitals around a central atom.

Square Pyramidal

Five atoms and one lone pair in octahedral shape.

Square Planar

Four atoms and two lone pairs in octahedral shape.

Resonance Structures

Multiple valid Lewis structures for a molecule.

Partial Charge

Unequal sharing of electrons in a bond.

Polarity

Determined by electronegativity differences in bonds.

Symmetry

Arrangement affecting molecular polarity.

dsp3 Hybridization

Hybridization for five occupied orbitals.

d2sp3 Hybridization

Hybridization for six occupied orbitals.

X-ray Crystallography

Technique to determine molecular structure.

Bonding Types

Includes ionic, covalent, metallic, and hydrogen bonds.

Electron Pair Repulsion

Causes molecular shapes to minimize electron pair interactions.

Pi Bond

Bond formed by the sideways overlap of p orbitals.

Sigma Bond

Single bond formed by head-on orbital overlap.