Chemistry Lecture Notes: Bonding, Periodic Table, and Stoichiometry

A set of vocabulary flashcards covering bonding types, periodic table groups, and basic stoichiometry concepts from the lecture.

Chemical Bond

The force that holds atoms together in a compound or molecule.

Octet Rule

Atoms are most stable when their valence shell has eight electrons (except hydrogen and helium).

Valence Shell

The outermost electron shell of an atom that determines bonding behavior.

Ionic Bond

A bond formed by transfer of electrons from a metal to a nonmetal, creating oppositely charged ions held together by electrostatic attraction.

Transfer of Electrons

Move electrons from one atom to another to form ions in ionic bonding.

Electrostatic Attraction

The force between oppositely charged ions that holds an ionic compound together.

Sodium Chloride (NaCl)

An ionic compound formed from Na+ and Cl−; common table salt.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic Compound

A compound composed of a lattice of cations and anions held by ionic bonds.

Crystal Lattice

A 3D repeating arrangement of ions in an ionic solid.

Covalent Bond

A bond formed by sharing electrons between nonmetal atoms.

Shared Electrons

Electrons counted as part of both bonding atoms in a covalent bond.

Molecule

A group of atoms held together by covalent bonds; the smallest unit of a covalently bonded substance.

Non-metals

Elements that are poor conductors and often gain electrons or share electrons in bonds.

Polar Covalent Bond

A covalent bond with unequal sharing of electrons, creating partial charges.

Nonpolar Covalent Bond

A covalent bond with equal sharing of electrons due to similar electronegativities.

Electronegativity

An atom’s tendency to attract electrons in a chemical bond; higher in nonmetals.

Periodic Table

A table organizing elements by increasing atomic number into periods and groups.

Dmitri Mendeleev

Scientist who organized the periodic table and predicted missing elements.

Period

A horizontal row in the periodic table indicating energy level occupancy.

Metals

Elements that are good conductors of electricity and typically form positive ions.

Non-metals (as a category)

Elements that are poor conductors and can gain electrons or form covalent bonds.

Metalloids

Elements with properties between metals and nonmetals.

Lanthanide

Inner-transition metals in the 4f block.

Actinide

Inner-transition metals in the 5f block.

Transition Metals

Elements with partially filled d subshells and multiple oxidation states.

Alkali Metals

Group 1 metals; highly reactive.

Alkaline Earth Metals

Group 2 metals; reactive but less so than alkali metals.

Group/Family

Vertical columns in the periodic table; elements with similar valence configurations.

Group IA (Alkali Metals)

Group 1 metals known for high reactivity.

Halogens

Group 17 nonmetals that form diatomic molecules (e.g., F2, Cl2).

Noble Gases

Group 18 inert gases with complete valence shells.

Ball-and-stick Model

A molecular model showing atoms as spheres connected by sticks to represent bonds.

Space-filling Model

A molecular model showing approximate sizes and spatial arrangement of atoms.

Hydrates

Compounds that contain water molecules incorporated into their crystal lattice.

Molar Mass

Mass of one mole of a substance, measured in g/mol.

Avogadro’s Number

6.022 × 10^23 particles per mole.

Mole

Amount of substance containing 6.022 × 10^23 particles.

Empirical Formula

The simplest whole-number ratio of elements in a compound.

Molecular Formula

The actual number of each type of atom in a molecule; may be a multiple of the empirical formula.

Percent Composition

The mass percentage of each element in a compound.

Stoichiometry

The study of quantitative relationships in chemical reactions using mole ratios.

CuSO4·5H2O

Copper(II) sulfate pentahydrate; a common hydrate.

Potassium Permanganate

KMnO4; a commonly used inorganic compound in stoichiometry problems.

Hydrate Examples

MgSO4·7H2O and CuSO4·5H2O illustrate hydrated salts.

Empirical to Molecular Formula (Steps)

Derive empirical formula from percent composition, find empirical molar mass, divide molar mass of compound by empirical molar mass to get n, then multiply empirical formula by n to obtain the molecular formula.