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A Beka Chemistry Test 5 (Chapters 7-8)

Terms in this set (58)

wave
a periodic back-and-forth motion that transmits energy
crests
the high points of a series of waves
troughs
the low points of a series of waves
wavelength
the distance between two corresponding points on successive waves
amplitiude
measure of the wave's strength; associated with the wave's height
frequency
the number of complete waves that pass by a point in a given time; inversely proportional to wavelength
hertz
the SI unit of wave frequency
particle theory of light
light consists of streams of tiny particles emitted by a light source; proposed by Sir Isaac Newton
wave theory of light
light consists of a series of waves
speed of electromagnetic waves (including light) in a vacuum
c=300,000,000 m/s (186,000 mi/s)
electromagnetic spectrum
the arrangement of all forms of electromagnetic radiation in order of frequency and wavelength
quantum theory of light
light consists of tiny packets of energy; consists of electromagnetic waves traveling as photons
photons
individual packets or quanta of light energy; their energy is proportional to their frequency
wave-particle duality
light has characteristics of both particles and waves
spectrometer
used to separate the colors for detailed study; used to compare the spectrum of a star to the spectra of elements on Earth
hydrogen spectrum
photons emitted as electrons drop from higher to lower energy levels
line spectrum
spectrum that contains only certain colors (wavelength)
continuous spectrum
spectrum that contains the complete array of colors
planetary model of the atom
proposed by Rutherford; does not take into account that electrons would collide with the nucleus
Bohr model of the atom
electrons move about the nucleus only in specific orbits (energy levels); does not take into account the spectra of atoms containing more than one electron
ground state
the lowest energy state of an electron
excited states
all states above the ground state
wave-mechanical (quantum-mechanical) model of the atom
an electron in an atom behaves as a 3D matter wave containing an integral number of wavelengths in an orbit
uncertainty principle
it is impossible to simultaneously determine the momentum and the position of an electron with precision
Born's interpretation
electrons are pointlike particles but move in indefinite orbitals around the nucleus instead of in fixed orbits
electron configuration
the complete arrangement of electrons in an atom; determines an atom's chemical behavior
principal quantum number
describes the electron shell of the electron
subshell quantum number
indicates the shape or type of subshell of the electron (s, p, d, f)
magnetic quantum number
describes the orientation in space of the orbital of the electron
spin quantum number
describes the electron's spin direction
Pauli exclusion principle
no 2 electrons in an atom may have the same set of 4 quantum numbers
aufbau principle
electrons occupy the lowest-energy orbital available, filling in orbitals of successively higher energies until all the electrons are distributed
Hund's rule
one electron will occupy each orbital in a subshell before pairing begins
electron repulsion
causes energy overlap between the electron shells; causes the 4s orbital to fill before the 3d orbitals
valence electrons
the electrons in the outermost shell of an atom; maximum number of 8 valence electrons in an atom; can be determined in the main-group elements by looking at the group number (p.e., group 13 has 3 valence electrons)
Lewis symbol
a representation of the outer-energy level electrons as dots written around the symbol for the element
Dmitri Mendeleev
developed the periodic table of the elements based on chemical properties
periodic law
the physical and chemical properties of the elements are periodic functions of their atomic numbers
group
elements in the same column of the periodic table
period
elements in the same row of the periodic table
nonmetals
elements found on the far right of the periodic table
metals
elements found on the left and center of the periodic table
semimetals (metalloids)
elements found between the metals and nonmetals on the periodic table
main-group elements (representative elements)
elements in columns 1-2 and 13-18 of the periodic table
transition metals
elements in columns 3-12 of the periodic table
inner transition metals
elements usually set off by themselves at the bottom of the periodic table
alkali metals
the elements in column 1; react with water to produce hydrogen gas and the metal hydroxide
alkaline earth metals
the elements in column 2; consists of elements that usually exist as 2+ ions
chalcogens
the elements in column 16
halogens ("salt-formers")
the elements in column 17
noble gases
the elements in column 18; rarely undergo chemical reactions
electron configuration abbreviation
the symbols for the noble gases are used to indicate that the elements that follow begin with the same configuration
atomic radius
increases going down a group, decreases across a period from left to right
ionic radius
simple cations are smaller than their neutral atoms; simple anions are larger than their neutral atoms
ionization energy
the energy required to remove an electron from an atom; first ionization energy decreases going down a group, increases across a period from left to right
metallic character
increases going down a group, decreases across a period from left to righ
electron affinity
the amount of energy involved in adding one electron to a gaseous atom of the element; values become more negative as metallic character decreases
electronegativity
the ability of chemically combined atoms to attract electrons to themselves; decreases going down a group, increases across a period from left to right
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