CHEM 201: Structure and Bonding

Flashcards covering key vocabulary terms related to electronic structure, bonding types (ionic, covalent, polar covalent, non-polar covalent), electronegativity, and molecular properties from the CHEM 201 lecture notes.

Electronegativity (χ)

The desire of one atom for the valence electrons of the neighboring atoms, used to predict or explain the type of bonding.

Electronegativity Difference (∆χ)

The difference in electronegativity between two atoms, which determines how valence electrons are distributed and can be used to predict the nature of bonding.

Ionic Bonding

Electrostatic forces (attractions) between positively and negatively charged ions that are closely packed together in a 3D lattice, typically formed when atoms with a large electronegativity difference (∆χ > 1.8) transfer valence electrons.

Covalent Bonding

The sharing of valence electrons between two atoms, occurring when atoms have fairly similar electronegativity values and a small electronegativity difference (∆χ ~ 0 – 1.8).

Non-polar Covalent Bond

A type of covalent bond where valence electrons are shared almost equally between two atoms due to a very small electronegativity difference (∆χ between 0 and 0.4).

Polar Covalent Bond

A type of covalent bond where valence electrons are shared unequally between two atoms due to an intermediate electronegativity difference (∆χ between 0.4 and 1.8), resulting in partial positive (δ+) and partial negative (δ-) charges.

Bond Dipole

An unbalanced distribution of electron density within a covalent bond, indicated by partial charges (δ+ and δ-) and an arrow pointing towards the more electronegative atom.

Valence Electrons

The electrons in the outermost shell of an atom that are involved in bonding interactions with other atoms.

Ionic Crystal

A crystalline solid compound composed of a repeated, three-dimensional arrangement (lattice structure) of cations and anions held together by electrostatic forces.

Empirical Formula

The smallest whole number ratio of cation to anion used to represent the composition of an ionic compound.

Delocalized Forces (Ionic Bonding)

The characteristic of ionic bonding where electrostatic attractions extend throughout a 3D lattice, rather than being confined to interactions between two specific atoms.

Localized Forces (Covalent Bonding)

The characteristic of covalent bonding where electron sharing occurs specifically between two bonded atoms, creating individual molecules.

Cation

A positively charged ion, formed when an atom loses one or more electrons.

Anion

A negatively charged ion, formed when an atom gains one or more electrons.

Polyatomic Ion

An ion composed of two or more atoms covalently bonded together, which as a unit carries an overall net positive or negative charge.

Electronegativity Trend

The general pattern that electronegativity increases from bottom to top in a group and from left to right in a period of the Periodic Table.

Electron Transfer

The complete movement of one or more valence electrons from one atom to another, resulting in the formation of ions and typically occurring in ionic bonding.

Chemical Species

A general term referring to atoms, molecules, ions, or collections of these, whose structure reflects properties of chemical substances.