Apologia Chemistry Module 07 Vocabulary

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Crookes tube

Back 1

glass tube used in experiments

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cathode ray tube

Back 2

another name for Crookes tube that is used in experiments

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atomic number

Back 3

tells you how many protons an atom contains

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isotopes

Back 4

Atoms with the same number of protons and electrons but different numbers of neutrons

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mass number

Back 5

The total number of neutrons and protons in an atom.

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isotopic enrichment

Back 6

In order to be able to produce a nuclear bomb, you must be able to artificially increase the amount of 235*U in the uranium that you are using. The way to do this, of course, is to get rid of some of the 238*U that is in your uranium. This process is called:

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model

Back 7

It is simply a constructed image of something that we cannot see with our eyes.

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alpha particles

Back 8

positive particles emitted by certain radioactive isotopes

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Rutherford model

Back 9

Also called the "planetary model of the atom" and developed by the same man who proved the Plum Pudding Model of the Atom was wrong.....

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nucleus

Back 10

center of the atom

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photons

Back 11

light is thought by some to be made up of these small particles

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particle/wave duality theory

Back 12

The theory that light sometimes behaves as a particle and sometimes behaves as a wave.

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crests

Back 13

The high points of the wave when trying to picture light.

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troughs

Back 14

The low points of the wave when trying to picture light.

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wavelength

Back 15

The distance between the crests (or troughs) of a wave.

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amplitude

Back 16

A measure of the height of the crests or the depths of the troughs on a wave.


The larger the amplitude, the bigger the wave.

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visible spectrum

Back 17

the range of light wavelengths that produces color

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physical constant

Back 18

A measurable quantity in nature that does not change.

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frequency

Back 19

The number of wave crests (or troughs) that pass a given point each second.

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“Hertz” (abbreviated “Hz”)

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The standard unit for frequency is simply 1/second.

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inversely related

Back 21

behave in the opposite way...

Such as in wave frequency and wavelengths:

for large wavelengths, frequency is small. Conversely, if wavelength is small, frequency is large.

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electromagnetic spectrum

Back 22

Our eyes, however, are only sensitive to the light contained in the visible spectrum; thus, that is the only light we perceive. But it is actually only a small part of the light that comes to us from the sun. It turns out that the sun bathes our planet with light of many, many different wavelengths and frequencies.

This entire light spectrum is called:

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electromagnetic radiation

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It means “light,” but it includes all wavelengths of light, not just the wavelengths that are visible.

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Planck's constant

Back 24

this constant allows us to relate energy and frequency. Its value is 6.63 x 10 -34 J/Hz.

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Joules

Back 25

an energy unit. (J)

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rods

Back 26

Cells in your eyes that are sensitive mostly to low levels of light and are not very sensitive to color.

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cones

Back 27

Cells in your eyes that respond to certain specific energies of light.

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spectrometer

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A scientific instrument that can analyze the light of a star and determine all of the individual wavelengths that make it up. Then, by matching the elements to their expected individual wavelengths, the elemental composition of the star can be determined.

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spectroscopy

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Method of analysis used to determine the elemental composition of a star and which can be applied to chemicals as easily as it is applied to stars.

(one of the most useful tools a chemist has in analyzing unknown substances.)

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Bohr's quantum assumption

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One very important advance that Bohr made in developing his model was his assumption that the electrons could only jump into and out of specific orbits. So, if an electron decided to jump out of orbit #1, it could not go just anywhere. It had to go into another allowed orbit, such as orbit #2. And even though it could be in orbit #1 and jump to orbit #2 , it could not be anywhere in between .

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an excited electron

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When an electron moves from an orbit close to the nucleus to an orbit far from the nucleus, we say that the electron has been ______________.

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de-excited electron

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When an electron moves from an orbit far from the nucleus to an orbit close to the nucleus, we say it has ____________.

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quantum mechanical model

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Today's updated model of the atom which is a bit more complicated than Bohr's model, but it still retains many of Bohr's concepts.

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orbitals

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Electrons do not orbit in fixed circles, but instead orbit in “clouds” where electrons can, at different times, be at different distances from the nucleus but still be in the same ___________. However, if you were to watch the electron for quite a while, you would see that it stayed within a certain boundary.

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ground state

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The lowest possible energy state for a given substance.

(it is different for every substance on earth.)

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electron configuration

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An abbreviation for an atom that tells the structure of that atom...........

1s*2 2s*2 2p*6 is for a neon atom

The numbers to the left of the letters represent the energy level, whereas the letters represent the shape of the orbital. The superscripted numbers tell you how many electrons are in the orbital. Thus, the abbreviation above tells us that there are two electrons in the 1s orbital, two electrons in the 2s orbital, and six electrons in the 2p orbitals.