The History and Models of the Atom

Dalton's Model

Elements combine in fixed ratios to form compounds.

Rutherford's Gold Foil Experiment

Demonstrated the nucleus' existence in atoms.

Quantum-Mechanical Model

Describes electron locations as probability distributions.

Isotopes

Atoms of the same element with different neutrons.

Democritus

500 B.C.
Proposed the concept of indivisible atoms.
(he had no proof of showing his idea)

Thomson's Model

Introduced the plum pudding or chocolate chip cookie model

Bohr Model

Electrons orbit the nucleus in defined paths.

Atomic Symbol

One or two-letter representation of an element.

Hyphen Notation

Element name followed by mass number (e.g., C-12).

Nuclear Symbol

Notation showing element, mass number, and atomic number.

Cations

Positively charged ions from losing electrons.

Anions

Negatively charged ions from gaining electrons.

Electron Configuration

Distribution of electrons among atomic orbitals.

Orbital Shapes

Geometric representation of electron probability regions.

Orbital Sizes

Indicates energy levels of electrons in atoms.

Shorthand Electron Configuration

Abbreviated notation using noble gas symbols.

Unpaired Electrons

Electrons that occupy separate orbitals singly.

Ground State

Lowest energy configuration of electrons in an atom.

Excited State

Higher energy state when electrons absorb energy.

The is when the electrons are in the lowest energy orbitals

ground state

The is achieved when the electrons jump to higher-energy orbitals

excited state

Atomic Theory

Foundation explaining matter's composition and behavior.

Building Blocks

Conceptual representation of atomic structure and interactions.

Energy Emission

Unique light colors emitted during electron transitions.

Electron Jump

Movement of electrons between energy levels.

Periodic Table

Organizes elements based on atomic structure and properties.

How many different orbital shapes?

(four) s, d, f, p