Ch 4 Inventory List

Vocabulary flashcards covering types of electron and molecular geometries, models, VSEPR theory, bond and molecular polarity, and intermolecular forces.

Linear Electron Geometry

Electron geometry with 2 electron groups around a central atom; 1800 apart.

Trigonal Planar Electron Geometry

Electron geometry with 3 electron groups around a central atom; 1200 apart in a flat triangle.

Tetrahedral Electron Geometry

Electron geometry with 4 electron groups around a central atom; 109.50 angles in a 3D shape.

Linear Molecular Geometry

Molecular geometry where all atoms are in a straight line; occurs with 2 bonding groups and no lone pairs.

Bent Molecular Geometry

Molecular geometry where atoms form a bent shape due to one or two lone pairs; common with 3 or 4 electron groups.

Trigonal Pyramidal Molecular Geometry

Molecular geometry with 3 bonding groups and 1 lone pair on a central atom, forming a 3D pyramid shape.

Ball and Stick Models

3D models that show atoms as balls and chemical bonds as sticks, illustrating the shape of a molecule.

Space-Filling Models

3D models that show atoms as overlapping spheres, representing the relative sizes and how closely atoms pack in a molecule.

Molecular Geometry

The 3D arrangement of atoms in a molecule, excluding lone pairs of electrons.

Electron Geometry

The 3D arrangement of all electron groups (bonding and lone pairs) around a central atom.

Electron Group

A region around a central atom where electrons are likely to be found4either a bond (single, double, triple) or a lone pair.

VSEPR (Valence Shell Electron Pair Repulsion)

A model used to predict molecular shapes based on the idea that electron groups repel each other and arrange themselves as far apart as possible.

Tetrahedral Molecular Geometry

Molecular geometry with 4 bonding groups and no lone pairs; atoms arranged in a 3D tetrahedron.

Bond Angle

The angle between two bonds around a central atom.

Electronegativity

A measure of how strongly an atom attracts electrons in a bond.

Electron Density Diagram

A visual representation of where electrons are likely to be in a molecule.

Partial Negative Charge (8-)

Occurs on the atom in a polar bond that pulls electrons closer to itself.

Partial Positive Charge (8+)

Occurs on the atom in a polar bond that has electrons pulled away from it.

Dipole

A separation of electrical charge in a bond or molecule, with a positive and a negative end.

Polar Covalent Bond

A covalent bond between two atoms with different electronegativities, leading to unequal sharing of electrons.

Dipole Arrow

A symbol (2) pointing from the partially positive atom to the partially negative atom, showing the direction of polarity.

Nonpolar Bonds

Covalent bonds where electrons are shared equally because the atoms have similar electronegativities.

Partial Charges

Small charges (8+ and 8-) that develop in polar bonds due to uneven electron sharing.

Polar Molecules

Molecules with an uneven distribution of charge, causing one end to be slightly negative and the other slightly positive.

Nonpolar Molecules

Molecules with an even distribution of charge; no net dipole.

Molecular Polarity

The overall polarity of a molecule, determined by its shape and bond polarities.

Hydrocarbons

Organic compounds made entirely of hydrogen and carbon atoms (e.g., methane, ethane).

Intermolecular Forces of Attraction

Forces between molecules, not within them. They determine physical properties like boiling and melting points.

Molecular Dipole

The overall direction of the dipole in a polar molecule.

Temporary Molecular Dipole

A brief uneven distribution of electrons in a nonpolar molecule, leading to weak attractions.

London dispersion forces

Weakest intermolecular forces caused by temporary dipoles; present in all molecules, especially nonpolar ones.

Dipole-dipole forces

Attractions between the positive end of one polar molecule and the negative end of another.

DNA (deoxyribonucleic acid )

The molecule that carries genetic information; its double helix structure is stabilized by hydrogen bonds between base pairs.

Hydrogen bonding

A strong type of dipole-dipole force that occurs when hydrogen is bonded to nitrogen (N), oxygen (O), or fluorine (F)