Atoms, Measurements, and the Periodic Table (Video Notes)

A vocabulary-style collection of key terms and definitions from the video notes, covering conversion factors, atomic structure, the periodic table, matter, and measurement concepts.

Dimensional analysis

A problem‑solving method that uses units as factors to convert between quantities.

Orbital

Regions of space around the nucleus where electrons are likely found; electrons do not move in fixed circles.

Nucleus

The central part of an atom containing protons and neutrons.

Atomic number

The number of protons in an atom's nucleus; determines the element.

Element

Substance composed of only one kind of atom; cannot be broken down into simpler substances chemically.

Symbol (element symbol)

A short notation for an element, usually one or two letters (e.g., C for carbon, O for oxygen).

Matter

Anything that has mass and takes up space.

Density

Mass per unit volume; a measure of how much matter is packed into a given space.

Atom

The basic unit of matter, composed of protons, neutrons, and electrons.

Neutron

Electrically neutral particle in the nucleus.

Accuracy

How close a measured value is to the true or accepted value.

Precision

How reproducible measurements are; the closeness of repeated measurements.

Mass

The amount of matter in an object; a measure of how much stuff it contains.