Chapter 7 Vocabulary

Question 1

Quantum-mechanical Model

Answer 1

A model that explains the behavior of absolutely small particles such as electrons and photons.

Question 2

Electromagnetic Radiation

Answer 2

A form of energy embodied in oscillating electric and magnetic fields.

Question 3

Amplitude

Answer 3

The vertical height of a crest (or depth of a trough) of a wave; a measure of wave intensity.

Question 4

Wave length (λ)

Answer 4

The distance between adjacent crests of a wave.

Question 5

Frequency (ν)

Answer 5

For waves, the number of cycles (or complete wavelengths) that pass through a stationary point in one second.

Question 6

Electromagnetic spectrum

Answer 6

The range of the wavelengths of all possible electromagnetic radiation.

Question 7

Gamma (γ) Rays

Answer 7

The form of electromagnetic radiation with the shortest wavelength and highest energy.

Question 8

X-Rays

Answer 8

Electromagnetic radiation with wavelengths slightly longer than those of gamma rays; used to image bones and internal organs.

Question 9

Ultraviolet (UV) Radiation

Answer 9

Electromagnetic radiation with slightly smaller wavelengths than visible light.

Question 10

Visible Light

Answer 10

Those frequencies of electromagnetic radiation that can be detected by the human eye.

Question 11

Infrared (IR) Radiation

Answer 11

Electromagnetic radiation emitted from warm objects, with wavelengths slightly larger than those of visible light.

Question 12

Microwaves

Answer 12

Electromagnetic radiation with wavelengths slightly longer than those of infrared radiation; used for radar and in microwave ovens.

Question 13

Radio Waves

Answer 13

The form of electromagnetic radiation with the longest wavelengths and smallest energy.

Question 14

Interference

Answer 14

The superposition of two or more waves overlapping in space, resulting in either an increase in amplitude (constructive interference) of a decrease in amplitude (destructive interference).

Question 15

Constructive Interference

Answer 15

The interaction of wave from two sources that align with overlapping crests, resulting in a wave of greater amplitude.

Question 16

Destructive Interference

Answer 16

The interaction fo waves from two sources aligned so that the crest of one overlaps the trough of the other, resulting in cancellation.

Question 17

Diffraction

Answer 17

The phenomena by which a wave emerging from an aperture spreads out to form a new wave front.

Question 18

Photoelectric Effect

Answer 18

The observation that many metals emit electrons when light falls upon them.

Question 19

Photon (quantum)

Answer 19

The smallest possible packet of electromagnetic radiation with an energy equal to hv.

Question 20

Emission Spectrum

Answer 20

The range of wavelengths emitted by a particular element; used to identify the element.

Question 21

de Broglie Relation

Answer 21

The observation that the wavelength of a particle is inversely proportional to its momentum λ= h/mv

Question 22

Complementary Properties

Answer 22

Those properties that exclude one another, i.e., the more you know about one, the less you know about the other. For example, the wave nature and particle nature of the electron are complementary.

Question 23

Heisenberg’s Uncertainty Principle

Answer 23

The principle stating that due to the wave-particle duality, it is fundamentally impossible to precisely determine both the position and velocity of a particle at a given moment in time.

Question 24

Deterministic

Answer 24

A characteristic of the classical laws of motion, which imply that present circumstances determine future events.

Question 25

Indeterminacy

Answer 25

The principle that present circumstances do not necessarily determine future events in the quantum-mechanical realm.

Question 26

Orbital

Answer 26

A probability distribution map, based on the quantum mechanical model of the atom, used to describe the likely position of an electron in an atom; also an allowed energy state for an electron.

Question 27

Wave Function

Answer 27

A mathematical function that describes the wavelike nature of the electron.

Question 28

Quantum Number

Answer 28

One of four interrelated numbers that determine the shape and energy of orbitals, as specified by a solution of the Schrodinger equation.

Question 29

Principal Quantum Number (n)

Answer 29

An integer that specifies the overall size and energy of an orbital. The higher the quantum number n, the greater the average distance between the electron and the nucleus and the higher its energy.

Question 30

Angular Momentum Quantum Number (l)

Answer 30

An integer that determines the shape of an orbital.

Question 31

Magnetic Quantum Number (ml)

Answer 31

An integer that specifies the orientation of an orbital.

Question 32

Principal level (shell)

Answer 32

The group of orbitals with the same value of n.

Question 33

Sublevel (subshell)

Answer 33

Those orbitals in the same principal level with the same value of n and l.

Question 34

Probability Density

Answer 34

The probability (per unit volume) of finding the electron at a point in space as expressed by a three-dimensional plot of the wave function squared.

Question 35

Radial Distribution Function

Answer 35

A function that represents the total probability of finding an electron within a thin spherical shell at a distance r from the nucleus.

Question 36

Node

Answer 36

A point where the wave function, and therefore the probability density and radial distribution function, all go through zero.

Question 37

Phase

Answer 37

The sign of the amplitude of a wave; can be positive or negative.