Physical Science: Molecular Polarity Flashcards

Vocabulary practice flashcards covering key terms and concepts in molecular polarity, covalent bonding, VSEPR theory, molecular geometries, and intermolecular interactions.

Valence electrons

Electrons found in the outermost energy level of an atom that are involved in chemical bonding and determining molecular arrangement.

Octet rule

The principle that stability for many atoms is associated with having $8$ valence electrons.

Covalent bond

A type of chemical bond formed when two atoms share electrons.

Single bond

A covalent bond formed by sharing $1$ pair of shared electrons.

Double bond

A covalent bond formed by sharing $2$ pairs of shared electrons.

Triple bond

A covalent bond formed by sharing $3$ pairs of shared electrons.

Lewis structure

A diagrammatic representation showing valence electrons, bonding electrons, lone pairs, and connections between atoms in a molecule.

Bonding pair

A pair of valence electrons shared between two atoms in a chemical bond.

Lone pair

A pair of nonbonding valence electrons on an atom that is not involved in bonding.

Electronegativity

The ability of an atom to attract shared electrons toward itself in a chemical bond.

Electronegativity trend order

The simplified relative electronegativity order among common elements: $\text{F} > \text{O} > \text{N} \approx \text{Cl} > \text{C} > \text{H}$.

Bond polarity

The unequal distribution of shared electrons in a bond caused by differences in electronegativity between the bonded atoms.

Nonpolar covalent bond

A bond formed between two identical atoms with equal electronegativities, resulting in equal electron sharing.

Bond dipole

The separation of partial positive ($\delta+$) and partial negative ($\delta-$) charges across a bond due to unequal electron distribution.

VSEPR Theory

Valence Shell Electron Pair Repulsion theory; states that electron pairs around a central atom repel one another and arrange themselves as far apart as possible.

Molecular geometry

The three-dimensional arrangement or shape formed by the atoms in a molecule.

Linear geometry

A molecular shape with an approximate bond angle of $180^\circ$, as seen in $\text{CO}_2$.

Trigonal planar geometry

A molecular shape with an approximate bond angle of $120^\circ$, as seen in $\text{BF}_3$.

Bent geometry

A molecular shape with an approximate bond angle of $104.5^\circ$ in $\text{H}_2\text{O}$, where nonbonding lone pairs repel bonding pairs.

Tetrahedral geometry

A molecular shape with an approximate bond angle of $109.5^\circ$, as seen in $\text{CH}_4$.

Trigonal pyramidal geometry

A molecular shape with an approximate bond angle of $\sim 107^\circ$, as seen in $\text{NH}_3$.

Charge distribution

The arrangement of positive ($\delta+$) and negative ($\delta-$) charges within a molecule.

Polar molecule

A molecule characterized by an overall uneven charge distribution and a net dipole moment.

Nonpolar molecule

A molecule with no overall permanent dipole, often due to symmetry that allows individual bond dipoles to cancel.

Intermolecular forces

Attractions between individual molecules that govern physical properties like solubility and boiling point.

Hydrogen bonding

A strong intermolecular force occurring when hydrogen is bonded to highly electronegative atoms such as $\text{N}$, $\text{O}$, or $\text{F}$.

London dispersion forces

Intermolecular forces experienced by nonpolar molecules that lack permanent dipoles.

Solubility

The ability of a given substance to dissolve in another substance.

Like dissolves like

The principle stating that substances with similar polarities and intermolecular forces tend to dissolve in one another.

Boiling point

The temperature at which a liquid changes into a gas throughout the liquid.