Chemistry - Chapter 1 - Atoms Flashcards

Vocabulary flashcards based on lecture notes about Atoms.

Atom

The basic building block of matter, consisting of a nucleus surrounded by electrons.

Nucleus

The small, dense region at the center of an atom, composed of protons and neutrons.

Protons

Positively charged particles located in the nucleus of an atom.

Neutrons

Neutral particles located in the nucleus of an atom.

Electrons

Negatively charged particles that orbit the nucleus of an atom.

Nucleons

A collective term for protons and neutrons found in the nucleus.

Quarks

The fundamental constituents of nucleons (protons and neutrons).

Strong Nuclear Force

The force that holds quarks together and holds nucleons together within the nucleus; it is stronger than the electromagnetic force but has a very short range.

Coulomb (C)

The SI unit of electric charge.

Fundamental Unit of Charge (e)

The elementary unit of electric charge, equal to the charge on one proton (1.6 x 10^-19 C).

Angstrom (Å)

A unit of length equal to 10^-10 meters, often used to express atomic sizes.

Nuclide

An atom specified by its number of protons and neutrons.

Mass Number (A)

The total number of protons and neutrons in the nucleus of an atom.

Atomic Number (Z)

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

Isotopes

Two or more forms of the same element that have the same number of protons but different numbers of neutrons.

Atomic Mass Unit (u)

A unit of mass approximately equal to the mass of one proton or one neutron, defined as one-twelfth the mass of a carbon-12 atom (1.66 x 10^-27 kg).

Atomic Weight (Ar)

A dimensionless quantity that represents an abundance-weighted average of hte masses of naturally occurring isotopes of an element.

Mole

A unit of measurement used in chemistry to express amounts of a chemical substance, defined as exactly 6.02214076 x 10^23 entities.

Avogadro's Number (NA)

The number of entities (atoms, molecules, ions, etc.) in one mole of a substance, approximately 6.022 x 10^23 mol^-1.

Molar Mass

The mass of one mole of a substance, usually expressed in grams per mole (g/mol).

Coulomb's Law

A law stating that the electrostatic force between two charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them.

Quantum

A discrete packet of energy, as described by Max Planck.

Planck's Constant (h)

A fundamental constant relating the energy of a photon to its frequency, approximately 6.626 x 10^-34 J s.

Photoelectric Effect

The emission of electrons from a material when light shines on it.

Threshold Frequency (fT)

The minimum frequency of incident light required to cause the photoelectric effect.

Work Function (Φ)

The minimum amount of energy required to remove an electron from a solid.

Line Spectra

Spectra containing only specific wavelengths of light, such as emission and absorption spectra.

Emission Line Spectrum

A spectrum of light emitted by excited atoms, consisting of discrete lines at specific wavelengths.

Absorption Line Spectrum

A spectrum of light that has passed through a substance, showing dark lines where specific wavelengths have been absorbed.

Bohr Atom

An idealized model of an atom in which electrons orbit the nucleus in specific circular paths corresponding to discrete energy levels.

Ground State

The lowest energy state of an atom or molecule.

Excited State

Any energy state of an atom or molecule that is higher than its ground state.

Balmer Series

A series of transitions of an electron in a hydrogen atom that result in the emission of photons at visible wavelengths.

Ionization Energy

The energy required to remove an electron completely from an atom or ion.

Heisenberg Uncertainty Principle

A principle stating that there is a fundamental limit to the precision with which certain pairs of physical properties of a particle, such as position and momentum, can be known simultaneously.

Atomic Orbital

A mathematical function that describes the wave-like behavior of an electron in an atom.