Module 3: Atomic Structure, Isotopic Abundance, and Nuclear Chemistry

Vocabulary flashcards covering atomic history, subatomic particles, isotopic abundance, measurement techniques, and basic nuclear chemistry.

Dalton's Atomic Theory

Theory stating that all matter is composed of tiny particles called atoms, which are identical in size, mass, and chemical properties for a given element, and combine to form compounds.

Law of Conservation of Mass

Principle supported by Dalton's atomic theory stating that mass is neither created nor destroyed during a chemical reaction.

Cathode Ray Tube Experiment

An experiment conducted by J.J. Thomson that led to the discovery of the electron.

Plum Pudding Model

An atomic model proposed by J.J. Thomson featuring negatively charged electrons embedded within a positively charged sphere.

Oil Drop Experiment

An experiment conducted by Millikan that determined the negative charge of an electron.

Gold Foil Experiment

An experiment performed by Rutherford demonstrating that an atom contains a dense, positively charged center called the nucleus.

Bohr Atomic Model

Model formulated by N. Bohr showing that electrons move within specific energy levels around the nucleus, where higher energy levels contain more energy.

Atomic Number

The number of protons in an atom's nucleus, which never changes and defines the identity of the element.

Mass Number

The total sum of protons and neutrons in the nucleus of an atom, calculated as $\text{Mass} = \#p + \#n$.

Isotopes

Atoms of the same element that have identical atomic numbers (same number of protons) but different numbers of neutrons and different mass numbers.

Hyphen Notation

A naming convention for isotopes that combines the element symbol or name with its mass number separated by a hyphen, such as $H-1$, $H-2$, and $H-3$.

Protium, Deuterium, and Tritium

The three isotopic forms of hydrogen, designated as $H-1$, $H-2$, and $H-3$ respectively.

Proton

A positively charged subatomic particle located inside the nucleus.

Neutron

The most massive subatomic particle, carrying a neutral charge and located inside the nucleus.

Electron

The smallest subatomic particle, carrying a negative charge and located within the energy levels of the electron cloud surrounding the nucleus.

Atomic Mass Unit (amu)

A unit of mass defined relative to the mass of Carbon-12 ($C-12$), where $1\,\text{amu}$ equals $\frac{1}{12}$ the mass of a Carbon-12 atom.

Average Atomic Mass

The weighted average mass of all naturally occurring isotopes of an element, calculated by converting isotopic abundances to decimals, multiplying by their respective isotopic masses, and adding the results.

Ion Formation

The creation of a net electric charge when a neutral atom gains electrons (becoming negatively charged) or loses electrons (becoming positively charged, e.g., $Al^{+3}$ losing 3 electrons).

Meniscus

The downward curve seen at the surface of a liquid in a container, measured at the bottom of the curve.

Graduated Cylinder Measurements

Volumetric measurements taken to the tenth place, where large cylinders have $1\,\text{mL}$ major marks with $0.5\,\text{mL}$ minor lines, and small cylinders have $1\,\text{mL}$ major marks with $0.2\,\text{mL}$ minor lines.

Unstable Nucleus

A nucleus containing an excessive ratio of neutrons, rendering the atom radioactive and causing it to emit nuclear radiation to gain stability.

Alpha Radiation

A type of nuclear radiation consisting of helium nuclei ($_2^4\text{He}$) that is the slowest and weakest form of radiation.

Beta Radiation

A form of nuclear radiation consisting of high-speed electrons ($_{-1}^0\beta$) emitted from an unstable nucleus during radioactive decay.

Gamma Radiation

The strongest and most penetrating type of nuclear radiation, represented by the symbol $\gamma$.