Chapter 4 chemistry

Planck's constant

6.626 x10 ^-34 Jxs where J is this symbol for the joule

Electromagnetic radiation

A form of energy that exhibits wavelike behavior as it travels through space

Beta particle

A high-speed electron with a 1- charge that is emitted during radioactive decay

Electron

A negatively charged, fast-moving particle with an extremely small mass that is found in all forms of matter and moves through the empty space surrounding an atom's nucleus

Neutron

A neutral, subatomic particle in an atom's nucleus that has a mass nearly equal to that of a proton

Alpha particle

A particle with two protons and two neutrons, with a 2+ charge; is equivalent to a helium-4 nucleus; and is emitted during radioactive decay

Nuclear reaction

A reaction that involves a change in the nucleus of an atom

Radioactive decay

A spontaneous process in which unstable nuclei lose energy by emitting radiation

Nuclear equation

A type of equation that shows the atomic number and mass number of the particles involved

Principal quantum number (n)

Assigned by the quantum mechanical model to indicate the relative sizes and energies of atomic orbitals

Isotope

Atom's of the same element with different numbers of neutrons

Quantum number

Bohr assigned a number , n

Principal energy level

Each major energy level

Valence electrons

Electrons in the atom's outermost orbitals- generally those orbitals associated with the atom's highest principal energy level

Beta radiation

Radiation that is made of beta particles

Gamma ray

High-energy radiation that has no electrical charge and no mass, is not deflected by electric or magnetic fields, usually accompanies alpha and beta radiation, and accounts for most of the energy lost during radioactive decay

Electromagnetic spectrum

Includes all forms of electromagnetic radiation, with the only differences in the types of radiation being their frequencies and wavelength

Photon

Massless particle that carries a quantum of energy

Radioactivity

The process in which some substances spontaneously emit radiation

Atomic mass unit

One-twelfth the mass of the isotopes of that element

De broglie equation

Predicts that all moving particles have wave characteristics

Energy sublevels

Principal energy levels contain

Alpha radiation

Radiation that is made up of alpha particles;is defected toward a negatively charged plate when radiation from a radioactive source is directed between two electrically charged plates

Cathode ray

Radiation that originates from cathode and travels to the anode of a cathode-Ray tube

Pauli exclusion principle

States that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins

Aufbau principle

States that each electron occupies the lowest energy orbital available

Dalton's atomic theory

States that matter is composed of extremely small particles called atoms

Hund's rule

States that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals

Proton

Subatomic particle in an atom's nucleus that has a positive charge of 1+

Heisenberg uncertainty principle

That it is fundamentally impossible to know precisely both the velocity and position of a particle at the same time

Radiation

The Rays and particles- alpha and beta particles and gamma rays-that are emitted by radioactive materials

Electron configuration

The arrangement of electrons in an atom

Quantum mechanical model of the atoms

The atomic model in which electrons are treated s waves

Electron-dot structure

The elements symbol, which represents the atomic nucleus and inner-level electrons, surrounded by dots representing all of the atom's valence electrons

Nucleus

The extremely small, positively charged, dense center of an atom that contains positively charged protons and neutral neutrons

Ground state

The lowest allowable energy state of an atom

Quantum

The minimum amount of energy that can be gained or lost by an atom

Mass number

The number after an elements name, representing the sum of its proton and neutrons

Frequency

The number of aves that pass a given point per second

Atomic number

The number of protons in an atom

Atomic emission

The set of frequencies of the electromagnetic waves emitted by atom's of the element

Wavelength

The shortest distance between equivalent points on a continuous wave

Atom

The smallest particle of an element that retains all the properties of that element

Atomic orbitals

The wave function predicts a three-dimensional region around the nucleus

Photoelectric effect

The wave model of light could not explain a phenomemon

Amplitude

The waves height from the origin to a crest or from the origin to a trough

Atomic mass

The weighted average mass of the isotopes of that element