Atomic Structure and Electromagnetic Radiation Vocabulary

Vocabulary flashcards covering key terms, scientists, subatomic particles, atomic models, and electromagnetic radiation properties from the lecture notes.

Wavelength

The distance between the crests of a wave, represented by the Greek letter lambda.

Frequency

The number of wave cycles to pass a given point per unit of time, represented by the Greek letter nu.

Hertz

The SI unit of cycles per second, used to measure frequency.

Electromagnetic radiation

Includes radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X-rays, and gamma rays.

Ground state

The state of an atom when its electron has its lowest possible energy.

Atomic emission spectrum

The specific wavelengths of spectral lines that are characteristic of an element.

Niels Bohr

A young Danish physicist and student of Rutherford who developed a new atomic model in 1913 to incorporate how the energy of an atom changes when it absorbs or emits light.

Orbits

Specific circular paths around the nucleus where an electron is found, as proposed by Bohr.

Energy levels

The fixed energies an electron can have in Bohr's model.

Quantum

An amount of energy required to move an electron from one energy level to another.

Atom

The smallest particle of an element that retains its identity in a chemical reaction.

Democritus

A Greek philosopher (460 BC - 370 BC) who reasoned that atoms were indivisible and indestructible.

John Dalton

An English chemist and schoolteacher (1766-1844) who transformed Democritus's ideas into a scientific theory known as the Billiard Ball Model.

Dalton's atomic theory

The theory stating that elements are composed of tiny indivisible particles called atoms, atoms of the same element are identical, atoms can mix or combine in simple whole-number ratios, and chemical reactions occur when atoms are separated, joined, or rearranged.

Subatomic particles

Smaller, fundamental particles that make up atoms, including electrons, protons, and neutrons.

Electrons

Negatively charged subatomic particles.

J. J. Thomson

An English physicist (1856-1940) who discovered the electron in 1897 using experiments with electric currents and glass tubes.

Eugen Goldstein

A scientist who, in 1886, observed a cathode-ray tube and found rays traveling in the opposite direction, concluding they were composed of positive particles.

Protons

Positively charged subatomic particles.

James Chadwick

An English physicist who confirmed the existence of the neutron in 1932.

Neutrons

Subatomic particles with no charge but with a mass nearly equal to that of a proton.

Ernest Rutherford

A scientist from New Zealand who devised the gold-foil experiment in 1911 to test the plum-pudding model of atomic structure.

Alpha particles

Helium atoms that have lost their two electrons and have a double positive charge, used as a narrow beam in Rutherford's experiment.

Nuclear atom

Rutherford's atomic model where the protons and neutrons are located in the positively charged nucleus, while electrons are distributed around the nucleus and occupy almost all the volume of the atom.

Nucleus

A tiny and densely packed region in the atom where all the positive charge and almost all the mass are concentrated.

Atomic number

The number of protons in the nucleus of an atom of that element, which identifies the element.

Mass number

The total number of protons and neutrons in an atom.

Isotopes

Atoms that have the same number of protons but different numbers of neutrons, making them chemically alike despite having different mass numbers.

Atomic mass unit (amu)

Defined as one-twelfth of the mass of a carbon-12 atom.

Atomic mass

A weighted average mass of the atoms in a naturally occurring sample of the element, reflecting both the mass and the relative abundance of the isotopes.

Electromagnetic spectrum order

Radiowave, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma ray.