Thomson was convinced that he had discovered a subatomic particle, the electron, from the evidence that
the charge to mass ratio was the same for all materials
the existence of a tiny, massive, and positively charged nucleus was deduced from the observation that
some radioactive particles were deflected by a magnetic foil
according to Rutherford's calculations, the volume of an atom is mostly,
empty space
Milikan measured the charge on oil droplets and found that all the droplets had
the same or multiples of the same charge
Rutherford's estimate of the radius of an atomic nucleus was based on
measurements of radioactive particle deflections from gold foil
the atomic number is the number of
protons
all neutral atoms of an element have the same
atomic number, number of electrons and number of protons
the main problem with a solar system model of the atom is that
the electron should lose energy since they are accelerating
atoms of an element that have different numbers of neutrons are
isotopes
the sum of the numbers of protons and neutrons in the nucleus of an atom is the
mass number
atomic weight is determined by
a weighted average of the masses of isotopes of an element based on abundance
this isotope provides the standard to which the masses of all other isotopes are compared
carbon- 12
in 1910, Max PLanck introduced the idea that matter emits and absorbs energy in
discrete units called quanta
energy of the electron is expressed in units of
electron volts
the major success of the Bohr theory was in explaining
the colors in the hydrogen line spectrum
light from an incandescent gas is dispersed into narrow lines of colors with no light between the lines. this is called
line spectrum
the lowest energy state or level of an atom is
ground state
the basis of the quantum mechanics theory of the atom is
the wave of electrons
an electron moving from an excited state to the ground state
emits a photon
the existence of matter waves proposed by
de Broglie
any moving particle hasa wavelength that is associated with it's mass and velocity. This is a statement that proposed the existence of
matter waves
the arrangement of electrons in orbitals is called
electron configuration
Group IIA elements are called
alkaline earth metals
the elements in A groups are called
representative elements
the element chlorine belongs to which groups?
Halogens
The gain or loss of electrons from an atom results in the formation of a
ion
elements that have properties of both the metals and nonmetals are
semiconductors
transition metals
are metal, belong to the B group, have variable charges
the energy of a photon
is directly proportional to the frequency
a photon of which of the following has the most energy? red light, orange light, green light, blue light
blue light
the lines of colors in a line spectrum from a given element
are always the same, with a regular spacing pattern
hydrogen, with it's one electron, produces a line spectrum in the visible light range with
four color lines
according to the Bohr model, an electron gains or loses energy only by
jumping from one allowed orbit to another
according to the bohr model, when an electron in a hydrogen atom jumps from an orbit farther from the nucleus to an orbit closer to the nucleus, it
emits a single photon with energy equal to the energy difference of the two orbits
the Bohr model of the atom
explained the color lines in the hydrogen spectrum, coud not explain the line spectrum of atoms larger than hydrogen, had some made-up rules without explanation
The Bohr model of the atom described the energy state of electrons with one quantum number. The quantum mechanics model uses how many quantum number to describe the energy state of an electron?
four
an electron in the second main energy level and second sublevel is described by the symbols
2p
the space in which it is probable that an electron will be found is described by a
orbital
two different isotopes of the same element have
the same number of protons and electrons but different numbers of neutrons
the isotopes of a given element always have
different masses and the same chemical behavior
If you want to know the number of protons in an atom of a given element. you look up
atomic number
if you want to know the number of neutrons in an atom of a given element, you
subtract the atomic number from the mass number
which of the following is always a whole number
mass number of a isotope
the quantum mechanics and Bohr models of the atom both agree on
how electrons are able to emit light
hydrogen with its one electron, can produce a line spectrum with four visible colors because
there are multiple energy levels that an electron can occupy
a photon is emitted from the electron structure of an atom when an electron
jumps from higher to a lower energy