Atomic Structure and Modern Atomic Theory

Vocabulary flashcards focusing on subatomic particles, energy states, electron behavior, atomic structure, and modern atomic models based on lecture notes.

Isotopes

Different versions of the exact same element that have the same number of protons but a different number of neutrons.

Ground State

The lowest possible energy state of an atom.

Excited State

Any condition where an atom has absorbed extra energy, causing electrons to jump to a higher energy level.

Proton

A subatomic particle located inside the nucleus with a +1 positive charge and a mass of $1\,\text{amu}$.

Neutron

A neutral subatomic particle located inside the nucleus with a charge of 0 and a mass of $1\,\text{amu}$.

Electron

A subatomic particle located outside the nucleus in the orbitals with a -1 negative charge and a mass of $0.00055\,\text{amu}$.

Atomic Number

The count of protons found in an atom's nucleus, which identifies the element.

Mass Number

The sum of protons and neutrons in an atom.

Atomic Mass

The physical weight of an element based on naturally occurring isotopes.

Neutral Atom

An atom in which the number of electrons equals the number of protons.

Gold Foil Experiment

An experiment that proved that atoms have a tiny, dense, positively charged nucleus and are mostly empty space.

Wave-Mechanical Model

The modern atomic theory developed in the 1920s by physicists like Erwin Shris dinger and Werner Heisenberg that treats electrons as waves with quantized energy levels rather than particles moving in fixed paths.

Orbital

A specific three-dimensional region of space around the nucleus where there is a high probability (typically 90% or greater) of finding an electron.

Electron Light Emission

The phenomenon where an electron produces light when returning from the excited state to the ground state.

Distribution of Charges in an Atom

The arrangement in an atom where positive charge is concentrated in a tiny central nucleus, while negative charge is spread out in a surrounding electron cloud.