HS Chemistry Unit 2: Data Analysis and Atomic Concepts

Vocabulary-style flashcards covering Unit 2: Data Analysis and Atomic Concepts, including measurement, scientific notation, atomic models, and electron configuration.

Mass

A measure of the amount of matter in an object.

Weight

The measure of gravitation pull on a matter; it is dependent on gravity and changes as gravity changes.

Volume

The amount of space occupied by an object.

Density

The ratio of mass to volume, expressed as $D = \frac{M}{V}$, with units such as $kg/m^3$, $g/cm^3$, or $g/mL$.

Uncertainty

The error that always exists in measurement; equipment with more decimal places usually has lower uncertainty.

SI Units

Le Systeme International d'Unites; a single measurement system used by scientists worldwide consisting of seven common base units.

Accuracy

The closeness of measurements to the correct or accepted value of the quantity measured.

Precision

Refers to the closeness of a set of measurements of the same quantity made in the same way.

Dimensional Analysis

A technique that uses conversion factors to convert one unit of measurement to another.

Scientific Notation

A way to handle very large or small numbers written in the form $M \times 10^n$, where $M$ is a number between 1 and 10.

Significant Figures

Consist of all the digits known with certainty in a measurement plus one final digit that is estimated or uncertain.

Independent Variable

The specific condition or variable that is changed by the scientist in an experiment.

Dependent Variable

The variable that is measured in an experiment and is directly affected by changes in the independent variable.

Atom

The smallest particle of an element that retains the properties of that element.

Proton

A positively charged subatomic particle located in the nucleus with a mass of $11\,amu$.

Neutron

A neutral subatomic particle located in the nucleus with a mass of $1\,amu$.

Electron

A negatively charged subatomic particle with a mass of approximately $0\,amu$ that moves around the nucleus in orbitals.

Atomic Number

A number that identifies the element and indicates the total number of protons in its nucleus.

Mass Number

The sum of the protons and neutrons in an atom's nucleus.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Average Atomic Mass

The weighted average of all the naturally occurring isotopes of a specific element.

Ground State

A stable state where electrons occupy the lowest possible energy levels.

Excited State

An unstable condition where electrons move to a higher energy level after absorbing energy.

Bright-line Spectrum

A spectrum produced when excited electrons drop back to the ground state and release energy in the form of light.

Orbital

A region in an atom where there is a high probability of finding an electron.

Valence Electrons

Electrons located in the outermost principal energy level ($n$) of an atom that determine chemical properties.

Principal Quantum Number ($n$)

The quantum number that designates the size of an orbital and matches the principal energy level.

Hund's Rule

The rule stating that a single electron must be placed into each orbital of a given sublevel before any electrons are paired.

Noble Gas Configuration

A shorthand method of writing electron configuration using the symbol of the previous noble gas followed by the remaining electron arrangement.

Substantial Change

A change signifying that a new substance has been created and the process is typically irreversible.