Chapter 3 Terms

Question 1

electromagnetic radiation

Answer 1

any form of radiant energy in the electromagnetic spectrum.

Question 2

electromagnetic spectrum

Answer 2

a continuous range of radiant energy that includes gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, and radio waves.

Question 3

wavelength (𝛌)

Answer 3

the distance from crest to crest or trough to trough on a wave.

Question 4

frequency (𝛎)

Answer 4

the number of crests of a wave that pass a stationary point of reference per second.

Question 5

hertz (Hz)

Answer 5

the SI unit of frequency with units of reciprocal seconds: 1 Hz = 1 s^-1 = 1 cycle per second (cps).

Question 6

Fraunhofer lines

Answer 6

a set of dark lines in the otherwise continuous solar spectrum

Question 7

atomic absorption spectra

Answer 7

characteristic patterns of dark lines produced when an external source of radiation passes through free gaseous atoms.

Question 8

quantum (plural quanta)

Answer 8

the smallest discrete quantity of a particular form of energy.

Question 9

Planck constant (h)

Answer 9

the proportionality constant between the energy and frequency of electromagnetic radiation expressed in E = hν; h = 6.626 x 10^-34 J ∙ s

Question 10

quantum theory

Answer 10

a model of matter and energy based on the principle that energy is absorbed or emitted in discrete packets, or quanta.

Question 11

quantized

Answer 11

having values restricted to whole-number multiples of a specific base value.

Question 12

photon

Answer 12

a quantum of electromagnetic radiation.

Question 13

photoelectric effect

Answer 13

the release of electrons from a material as a result of electromagnetic radiation striking it.

Question 14

threshold frequency (𝛎0)

Answer 14

the minimum frequency of light required to produce the photoelectric effect.

Question 15

work function (𝚽)

Answer 15

the amount of energy needed to dislodge an electron from the surface of a material.

Question 16

ground state

Answer 16

the most stable, lowest energy state of a particle.

Question 17

excited state

Answer 17

any energy state above the ground state.

Question 18

electron transition

Answer 18

movement of an electron between energy levels.

Question 19

de Broglie equation

Answer 19

relates the wavelength of any moving object to its mass and its speed.

Question 20

matter wave

Answer 20

the wave associated with any moving particle.

Question 21

Heisenberg uncertainty principle

Answer 21

the principle that one cannot simultaneously know the exact position and the exact momentum of an electron.

Question 22

wave mechanics or quantum mechanics

Answer 22

a mathematical description of the wavelike behavior

Question 23

Schrödinger wave equation

Answer 23

a description of how the electron matter wave varies with location and time around the nucleus of a hydrogen atom.

Question 24

wave function (𝛙)

Answer 24

a solution to the Schrödinger wave equation describing how the matter wave of an electron varies in both time and location in an atom.

Question 25

orbitals

Answer 25

defined by the square of the wave function (ψ^2); regions in an atom where the probability of finding an electron is high.

Question 26

quantum number

Answer 26

one of four related numbers that specify the energy, shape, and orientation of orbitals in an atom and the spin orientation of electrons in the orbitals.

Question 27

principal quantum number (n)

Answer 27

a positive integer describing the relative size and energy of an atomic orbital or group of orbitals in an atom.

Question 28

angular momentum quantum number (l)

Answer 28

an integer having any value from 0 to (n - 1) that defines the shape of an orbital.

Question 29

magnetic quantum number (mO)

Answer 29

defines the orientation of an orbital in space; an integer that may have any value from 2/ to 1/, where/ is the angular momentum quantum number.

Question 30

spin quantum number (ms)

Answer 30

either 1/2 or -1/2, indicating the spin orientation of an electron.

Question 31

Pauli exclusion principle

Answer 31

principle that states no two electrons in an atom can have the same set of four quantum numbers.

Question 32

aufbau principle

Answer 32

the concept of building up ground state atoms so that their electrons occupy the lowest energy orbitals available.

Question 33

electron configuration

Answer 33

the distribution of electrons among the orbitals of an atom or ion

Question 34

effective nuclear charge (Zeff)

Answer 34

the attraction toward the nucleus experienced by an electron in an atom; the positive charge on the nucleus is reduced by the extent to which other electrons in the atom shield the electron from the nucleus.

Question 35

core electrons

Answer 35

electrons in the filled, inner shells in an atom or ion that are not involved in chemical reactions.

Question 36

valence electrons

Answer 36

electrons in the outermost occupied shell of an atom having the most influence on the atom’s chemical behavior.

Question 37

valence shell

Answer 37

the outermost occupied shell of an atom.

Question 38

Hund’s rule

Answer 38

the lowest energy electron configuration of an atom has the maximum number of unpaired electrons, all of which have the same spin, in degenerate orbitals.

Question 39

orbital diagram

Answer 39

a depiction of the arrangement of electrons in an atom or ion using boxes to represent orbitals.