Chapter 4 Key Terms

Question 1

electromagnetic radiation

Answer 1

form of energy consisting of waves and made up of oscillating electric and magnetic fields at right angles to each other

Question 2

amplitude

Answer 2

height of a wave measured from its origin to its crest

Question 3

wavelength

Answer 3

distance between successive crests of the wave

Question 4

frequency

Answer 4

number of waves that pass a certain point in a given amount of time

Question 5

speed of light (c)

Answer 5

speed at which light waves travel; 3.00 x 10(superscript 8) meters per second (m/s) in a vacuum

Question 6

visible spectrum

Answer 6

a continuous spectrum containing the array of colors from violet, to indigo, to blue, to green, to yellow, to orange, to red

Question 7

quantum

Answer 7

word meaning fixed amount (plural = quanta)

Question 8

Planck’s constant

Answer 8

h in the equation relating energy, E, to the frequency, v, of the radiation that goes as follows: E= hv. It has a value of 6.6261 x 10(superscript-34) Joules per second

Question 9

photoelectric effect

Answer 9

phenomenon in which light can be used to knock electrons out of a metal; can be explained only in terms of the particle nature of radiant energy

Question 10

photon

Answer 10

quantum for electromagnetic energy

Question 11

line spectrum

Answer 11

a spectrum that contains only certain colors, or wavelengths (as opposed to a continuous spectrum)

Question 12

quantum number

Answer 12

n; a labeling of each energy level, and consequently each orbit, that was given to them by Bohr

Question 13

ground state

Answer 13

lowest energy level, in which n=1

Question 14

excited state

Answer 14

a level of higher energy to which an electron can jump if it absorbs the appropriate amount of energy which has a quantum number n=2, n=3, n=4, and so on

Question 15

matter wave

Answer 15

the wavelike behavior of particles as referred to by De Broglie

Question 16

uncertainty principle

Answer 16

states that it is impossible to know the position and momentum of particles exactly (the position and the momentum of a moving object cannot simultaneously be measured and known exactly)

Question 17

quantum-mechanical model (of the atom)

Answer 17

explains the properties of atoms by treating the electron as a wave and by including the idea of quantized energies

Question 18

electron density

Answer 18

the density of an electron cloud (where the density of a region has a positive relationship to the probability of finding an electron in that region)

Question 19

orbital

Answer 19

a region in the space around the nucleus of an atom where an electron with a particular energy is likely to be found

Question 20

principal energy level

Answer 20

one of a limited limited number of energy levels in an atom, designated by the quantum number (n) of that prinicipal energy (i.e. n=1), and whose number of sublevels is determined by that quantum number (i.e. for n=1 there is a single sublevel (s), for n=2 , two sublevels (s and p)

Question 21

sulevel

Answer 21

a division of a principal energy level in an atom (i.e. sublevels s, p, d, and f)

Question 22

electron configuration (of an atom)

Answer 22

distribution of electrons among the orbitals of the atom determined by distributing the atom’s electrons among levels, sublevels, and orbitals based on a set of stated principles

Question 23

orbital diagram

Answer 23

representation of an atom in which arrows in boxes are used to show the electron configuration of an atom