Chemistry Chapter 10: Electron Geometry

Study Notes

Electron Geometry and Molecular Geometry

Electron geometry determines the spatial arrangement of electron groups around a central atom.
Molecules CF4 (Tetrahedral), NF3 (Trigonal Pyramidal), OF2 (Bent), and H2S (Bent) demonstrate varied molecular geometries despite sharing the same electron geometry classification as tetrahedral.

VSEPR Theory

Valence-Shell Electron-Pair Repulsion Theory (VSEPR) states that electron pairs (bonding and lone pairs) repel each other, influencing molecular shape.
Electron pair repulsions dictate the distances between electron groups, which forms the basis for predicting molecular geometry.

Bond Angles

Linear molecular geometry has a bond angle of 180 degrees.
Tetrahedral shape has bond angles of 109.5 degrees.
Trigonal planar configuration has bond angles of 120 degrees.
Trigonal bipyramidal has bond angles of 120 degrees and 90 degrees.
Octahedral geometry features bond angles of 90 degrees.
Deviations from ideal bond angles occur due to lone pairs and multiple bonds that occupy more space than single bonds, affecting angle measurements.

Polarity of Molecules

BrF5 is polar due to the presence of polar bonds and dipole moments within the molecule.

Bond Order

Bond order indicates the number of bonds between atoms and helps in assessing stability; Li2− possesses a bond order of 0.5.

Magnetism and Electron Configuration

Li2− is classified as paramagnetic because it contains unpaired electrons, which affect its magnetic properties.

Electronegativity Ranges

Nonpolar covalent bonds typically have an electronegativity difference of 0-0.4.
Polar covalent bonds have an electronegativity difference ranging from 0.4 to 1.8.
Ionic bonds are present when the electronegativity difference exceeds 1.8.

Atomic Orbitals and Hybridization

The number of standard atomic orbitals contributes to the formation of an equal number of hybrid atomic orbitals during hybridization processes.
Bonding orbitals have lower energy than their corresponding antibonding orbitals, indicating stability in molecular formations.

C-Cl Bond Formation

Specific atomic orbitals overlap to form bonds in molecules, such as the C-Cl bond in CH3Cl, which requires further detail on the types of orbitals involved.

Description

Test your knowledge of electron geometry and molecular shapes with flashcards focusing on CF4, NF3, OF2, and H2S. Understand the differences between tetrahedral and trigonal pyramidal structures. This quiz is ideal for students studying molecular geometry in Chemistry.