Chemistry Lecture Review

A set of vocabulary flashcards covering key chemistry concepts, terms, and definitions from the lecture.

Atom

The basic unit of all the known elements on Earth.

Bohr's Model

An atomic model depicting a small, positively charged nucleus surrounded by electrons in circular orbits, introduced by Niels Bohr in 1913.

Nucleus

The part of the atom that contains protons and neutrons.

Valence Electrons

Electrons in the outer-most shell, responsible for forming bonds during chemical reactions.

Electron Configuration

The number of electrons in each shell for a specific atom.

Periodic Table

A table containing the building blocks of elements organized by atomic number.

Atomic Number

The number of protons in the nucleus of an atom.

Atomic Mass

The average mass of an element’s isotopes, rounded to the nearest whole number.

Compound

A substance made of two or more different elements that are chemically joined in a fixed ratio.

Mixture

A combination of two or more elements or compounds without chemical bonding.

Chemical Equation

A representation of a chemical reaction showcasing the reactants and products.

Collision Theory

A theory stating that for a reaction to occur, reacting particles must collide with sufficient energy and proper orientation.

Catalyst

A substance that speeds up a chemical reaction without being consumed in the process.

Endothermic Reaction

A reaction that absorbs energy from the surroundings, usually felt as cold.

Exothermic Reaction

A reaction that releases energy, usually felt as warmth.

Chemical Change

A process that involves the formation of new substances with different properties.

Physical Change

A change that affects one or more physical properties of a substance without altering its chemical composition.

Law of Conservation of Mass

The principle stating that mass cannot be created or destroyed in a chemical reaction.

Precipitate

A solid that forms from the reaction between two solutions.

Reaction Rate

The speed at which a chemical reaction proceeds.

Isotopes

Atoms of the same element that have different numbers of neutrons.