Chapter 7

Question 1

absorption spectrum

Answer 1

the spectrum produced when atoms absorb specific wavelengths of incoming light and become excited from lower to higher energy levels

Question 2

amplitude

Answer 2

the height of the crest (or depth of the trough) of a wave; related to the intensity of the energy (brightness of the light)

Question 3

angular momentum quantum number (l)

Answer 3

an integer from 0 to n − 1 that is related to the shape of an atomic orbital

Question 4

atomic orbital

Answer 4

the wave function of an electron in an atom. the term is used qualitatively to mean the region of space in which there is a high probability of finding the electron

Question 5

d orbital

Answer 5

an atomic orbital with l = 2

Question 6

de Broglie wavelength

Answer 6

the wavelength of a moving particle obtained from the de Broglie equation: λ = h/mu

Question 7

diffraction

Answer 7

he phenomenon in which a wave striking the edge of an object bends around it. a wave passing through a slit as wide as its wavelength forms a circular wave

Question 8

electromagnetic radiation

Answer 8

oscillating, perpendicular electric and magnetic fields moving simultaneously through space as waves and manifested as visible light, x-rays, microwaves, radio waves, and so on

Question 9

electromagnetic spectrum

Answer 9

the continuum of radiant energy arranged in order of increasing wavelength

Question 10

electron cloud depiction

Answer 10

an imaginary representation of an electron’s rapidly changing position around the nucleus over time

Question 11

electron density diagram

Answer 11

the pictorial representation for a given energy sublevel of the quantity ψ2 (the probability density of the electron lying within a particular tiny volume) as a function of r (distance from the nucleus)

Question 12

emission spectrum

Answer 12

the line spectrum produced when excited atoms return to lower energy levels and emit photons characteristic of the element

Question 13

excited state

Answer 13

any electron configuration of an atom (or ion or molecule) other than the lowest energy (ground) state

Question 14

f orbital

Answer 14

an atomic orbital with l = 3

Question 15

flame test

Answer 15

a procedure for identifying the presence of metal ions in which a granule of a compound or a drop of its solution is placed in a flame to observe a characteristic color

Question 16

frequency

Answer 16

the number of complete waves, or cycles, that pass a given point per second, expressed in units of 1/second, or s−1 [also called hertz (Hz)]; related inversely to wavelength

Question 17

ground state

Answer 17

the electron configuration of an atom (or ion or molecule) that is lowest in energy

Question 18

infrared (IR)

Answer 18

the region of the electromagnetic spectrum between the microwave and visible regions

Question 19

level (shell)

Answer 19

a specific energy state of an atom given by the principal quantum number n

Question 20

line spectrum

Answer 20

a series of separated lines of different colors representing photons whose wavelengths are characteristic of an element

Question 21

magnetic quantum number

Answer 21

an integer from −l through 0 to +l that specifies the orientation of an atomic orbital in the three-dimensional space about the nucleus

Question 22

node

Answer 22

a region of an orbital where the probability of finding the electron is zero

Question 23

p orbital

Answer 23

an atomic orbital with l = 1

Question 24

photoelectric effect

Answer 24

the observation that, when monochromatic light of sufficient frequency shines on a metal, an electric current is produced

Question 25

photon

Answer 25

a quantum of electromagnetic radiation

Question 26

Planck's constant (h)

Answer 26

a proportionality constant relating the energy and frequency of a photon, equal to 6.626 × 10−34 J·s

Question 27

principal quantum number (n)

Answer 27

a positive integer that specifies the energy and relative size of an atomic orbital; a number that specifies an energy level in an atom

Question 28

probability contour

Answer 28

a shape that defines the volume around an atomic nucleus within which an electron spends a given percentage of its time

Question 29

quantum

Answer 29

a packet of energy equal to hν. the smallest quantity of energy that can be emitted or absorbed

Question 30

quantum mechanics

Answer 30

the branch of physics that examines the wave nature of objects on the atomic scale

Question 31

quantum number

Answer 31

a number that specifies a property of an orbital or an electron

Question 32

radial probability distribution plot

Answer 32

the graphic depiction of the total probability distribution (sum of ψ2) of an electron in the region near the nucleus

Question 33

refraction

Answer 33

a phenomenon in which a wave changes its speed and therefore its direction as it passes through a phase boundary into a different medium

Question 34

s orbital

Answer 34

an atomic orbital with l = 0

Question 35

Schrodinger equation

Answer 35

an equation that describes how the electron matter-wave changes in space around the nucleus. solutions of the equation provide energy states associated with the atomic orbitals

Question 36

spectrometry

Answer 36

any instrumental technique that uses a portion of the electromagnetic spectrum to measure the atomic and molecular energy levels of a substance

Question 37

speed of light (c)

Answer 37

a fundamental constant giving the speed at which electromagnetic radiation travels in a vacuum: c = 2.99792458 × 108 m/s

Question 38

stationary state

Answer 38

in the Bohr model, one of the allowable energy levels of the atom in which it does not release or absorb energy

Question 39

sublevel (subshell)

Answer 39

an energy substate of an atom within a level. given by the n and l values, the sublevel designates the size and shape of the atomic orbitals

Question 40

ultraviolet (UV)

Answer 40

radiation in the region of the electromagnetic spectrum between the visible and the x-ray regions

Question 41

uncertainty principle

Answer 41

the principle stated by Heisenberg that it is impossible to know simultaneously the exact position and velocity of a particle; the principle becomes important only for particles of very small mass

Question 42

wavelength

Answer 42

the distance between any point on a wave and the corresponding point on the next wave, that is, the distance a wave travels during one cycle

Question 43

wave-particle duality

Answer 43

the principle stating that both matter and energy have wavelike and particle-like properties