2 ATOMIC THEORY Flashcards
what are the quantum numbers?
principle, orbital, magnetic, spin
what does principle number represent?
n; wave function type; number of nodes (n-1)
what does orbital number represent?
l; which orbital its in; s0 p1 d2 f3
what does magnetic number represent?
ml; xyz; orientation of orbital; depends on l
what does spin number represent?
ms; identifies the two electrons in orbital; each electron has a diff spin; +1/2 or -1/2
what is an orbital node?
point in a wave that is never displaced; where wave function and wavefunction^2 change phase; at a node - the electron density is 0
what is electron density?
possibility of finding electron
what are the rules to consider when placing electrons in orbitals?
aufbau: electrons added to lowest level - pauli: no two electron can have the same set of quantum numbers - hund: same spin maximized, half fill subshells first
what does a longer wavelength indicate?
lower frequency
what does changing amplitudes do?
affects intensity (e.g. brightness, volume, etc)
what is the range of the visible spectrum? and which colour is lowest?
approx 400nm-750nm; violet - red
what are the colours in the visible hydrogen emission spectrum?
violet, blue, blue-green, red
what is the order in the electromagnetic spectrum from smallest wavelength to highest? (or highest frequency to smallest)
gamma rays, x rays, uv, visible, infrared, microwaves, radio
what is the rydberg formula used for?
used to determine wavelength of electron moving between energy levels
what is diffraction?
the bending of light
when does constructive interference occur and what is the result?
when two wavelengths are in phase; wavelengths added
when does destructive interference occur and what is the result?
when wavelength’s maxima is aligned with the others minima; wavelengths cancel out to zero
what occurs when a beam of light is used in the double slit experiment?
an interference pattern is produced
what occurs when a stream of particles is used in the double slit experiment?
two bright bands are produced but no interference pattern
what can the double slit experiment be used for?
to distinguish between waves and particles
what is bregolis equation used for what did he propose?
relating mass and velocity; proposed that electrons exhibit wavelike behavior in addition to particle-like properties
what is a standing wave?
a wave thats bound and only oscillates at certain frequencies
how do electrons travel if they cant be at the node?
they cross thru quantum tunneling
why do orbitals in the same shell differ in energy?
this is due to electron repulsion
what does isoelectronic mean?
atoms with the same charge; includes anions and cations
what is effective nuclear charge?
the net positive charge experienced by the valence electrons, accounting for
screening from the core electrons
patterns in the periodic table: bond length and size of atoms/ions
increase in size as you go down pt. decrease in size as you go right pt.
patterns in the periodic table: ionization energy
decrease in size as you go down pt. increase in size as you go right pt.
patterns in the periodic table: electron affinity
decrease in size as you go down pt. increase in size as you go right pt.
patterns in the periodic table: electronegativity
decrease in size as you go down pt. increase in size as you go right pt.
what is ionization energy?
energy needed to remove electron from gaseous atom; with each successive ionization the energy needed to remove electrons increase (enthalpy H = +)
what is electron affinity?
energy change when gaseous atom gains electron; with each successive addition, energy required decreases (enthalpy more favourable H = -)
what is electronegativity?
ability of atom in molecule to draw electron density of a bond (pairs of electrons) to itself
what conclusion can be drawn from the double slit experiment?
electrons possess the properties of waves
according to bohr’s model of hydrogen, why is the jump from 5to4 smaller than 2to1?
the energy gap decreases as n increases, which is also
why orbitals such as 5s and 4d are so close in energy)
although there is a trend in electron affinity on the pt, it is important to note that…?
more energy is required when adding electrons to a new orbital!
what do charges indicate about the size of an atom?
more electron charge means bigger size. anion>cation
how are the energy, wavelength, and frequency of electromagnetic radiation related?
energy of electromagnetic radiation inversely proportional to its wavelength. short wavelength = higher energy.
frequency is how many times the wave repeats itself. shorter wavelength = higher frequency.
energy and frequency are directly proportional. higher energy = higher frequency.
explain the bohr model
electron in hydrogen occupies lowest energy level (ground state). if electron absorbs energy, it promotes, reaching excited state. because excited state isnt stable electron will return to original state emitting energy as light. this energy difference corresponds to light of certain wavelength.
explain the origin of balmer, lyman, paschen series using the bohr model. list the energy levels and the spectrum it falls into
refers to the wavelength emitted when electron falls from a higher energy level to (BALMER) n=2 visible light, (LYMAN) n=1 UV, (PASCHEN) n=3 infrared.
explain in the context of quantum mechanics, what a node is.
area where the value of Ψ(x) is 0. it occurs at the point where wave changes phase (other than the fixed ends of the wave). it is where there is 0 probability of finding an electron
in quantum mechanics, what is the definition of an orbital?
area of space around the nucleus where an electron is most likely to be found within 90% probability
