Study Notes for Exam on Chemical Bonding and Molecular Geometry

covalent bonds

Covalent bonds are chemical bonds that involve the sharing of electron pairs between atoms, allowing each atom to attain the electron configuration of a noble gas.

electronegativity

the tendency of an atom to attract electrons in a chemical bond.

binary molecular compunds

compounds formed from two nonmetals that share electrons through covalent bonds.

lewis structures

diagrams that represent the bonding between atoms in a molecule, using dots to depict valence electrons and lines for covalent bonds.

octet rule

the principle that atoms tend to bond in such a way that they each have eight electrons in their valence shell, achieving a stable electron configuration.

expanded octet

a situation in which an atom contains more than eight electrons in its valence shell, often observed in elements from period three or below.

NASL method

a systematic approach for determining the molecular geometry and polarity of a molecule based on its Lewis structure. stands for needed, available, surrounding, lone pairs.

resonance

the phenomenon where two or more valid Lewis structures can describe a molecule, reflecting the delocalization of electrons.

electron geometry

the spatial arrangement of electron pairs around a central atom, which can be determined from the number of bonding and non-bonding electron pairs.

electron domains

regions in space around a central atom where electron pairs are likely to be found, including bonding and lone pairs.

central atom

the atom in a molecule that is bonded to other atoms and typically possesses the highest bonding capacity, determining the molecular shape.

molecular geometry

the three-dimensional arrangement of atoms in a molecule, determined by the positions of bonded atoms and lone pairs around the central atom.

electron domain

the spatial regions around a central atom where bonding or lone pairs of electrons reside.

lone pairs

pairs of valence electrons that are not involved in bonding and occupy space around the central atom, affecting molecular geometry.

terminal atoms

atoms located at the ends of a molecule or structure that are bonded to the central atom.

polar vs nonpolar

A comparison of molecules based on the distribution of electron density, determining their overall dipole moment. Polar molecules have an unequal sharing of electrons, while nonpolar molecules have an equal sharing.

IMF

Intermolecular forces that occur between molecules, influencing physical properties like boiling and melting points.

bond dipoles

vector quantities that show the polarity of a bond due to differences in electronegativity between bonded atoms.

hydrogen bonding

a strong type of dipole-dipole interaction that occurs between molecules containing hydrogen bonded to highly electronegative atoms such as nitrogen, oxygen, or fluorine.

LDF

(London dispersion forces) weak intermolecular forces caused by temporary shifts in electron density that induce polarization in neighboring molecules.

dipole dipole

interactions between polar molecules that arise from the electrostatic attraction between the dipoles of different molecules.

emperical formula

a chemical formula that shows the simplest whole-number ratio of elements in a compound, rather than the actual number of atoms.

percent composition

polarity

the tendency of a molecule to have a positive and negative end due to uneven distribution of electron density.