Ch. 4 Organizaciones de Electrones dentro de un Átomo

Electromagnetic radiation

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

Electromagnetic spectrum

Formed by all the forms of electromagnetic radiation together.

Wavelength

The distance between corresponding points on adjacent waves (m).

Frequency

The number of waves that pass a given point at a specific time, usually one second (s^-1).

Photoelectric effect

Refers to the emission of electrons from a metal when light shines on the metal.

Quantum

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

Energy

The energy in joules of a quantum of radiation (E).

Photon

A particle of electromagnetic radiation having zero mass and carrying a quantum of energy.

Ground state

The lowest energy state of an atom.

Excited state

Higher potential energy of atoms rather than it had in its ground state.

Orbits

Where the electron can circle the nucleus.

Emission

The process when an electron falls to a lower energy level, a photon is emitted.

Absorption

Process where energy must be added to an atom to move an electron from a lower energy level to a higher energy level.

Diffraction

The bending of a wave as it passes by the edge of an object or through a small opening.

Interference

Occurs when waves overlap.

Heisenberg uncertainty principle

States that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle.

Quantum theory

Describes mathematically the wave properties of electrons and other very small particles.

Orbitals

Where electrons exist, a three-dimensional region around the nucleus that indicates the probable location of an electron.

Principal quantum number

Indicates the main energy level occupied by the electron (n).

Angular momentum quantum number

Indicates the shape of the orbital (l).

Magnetic quantum number

Indicates the orientation of an orbital (m).

Spin quantum number

Has only two possible values-(+1/2, -1/2)- which indicate the two fundamental spin states of an electron in an orbital.

Electron configuration

The arrangement of electrons in an atom.

Ground-state electron configuration

The lowest-energy arrangement of the electrons for each element.

Aufbau principle

An electron occupies the lowest-energy orbital that can receive it.

Pauli exclusion principle

No two electrons in the same atom can have the same set of four quantum numbers.

Hund’s rule

Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state.

Orbital notation

An occupied orbital is represented by a line, with the orbital’s name written underneath the line.

Electron-configuration notation

The number of electrons in a sublevel is shown by adding a superscript to the sublevel designation.

Highest-occupied energy level

The electron-containing main energy level with the highest principal quantum number.

Inner-shell electrons

These are the electrons that are not in the highest-occupied energy level.

Noble-gas configuration

Refers to an outer main energy level occupied, in most cases, by eight electrons.