THE BOHR ATOM Flashcards
Although the Bohr model is not completely accurate, it can be used to explain
absorption and emission
Electrons move from low energy to higher energy orbits by
absorbing energy
Electrons move from high energy to lower energy orbits by
emitting energy
Electron energy is
quantized
the higher the wavelength, the lower the energy
the higher the energy, the lower the wavelength
n
principal quantum numbers
describes the energy level on which the orbital residue
- numbers greater than 0
Quantum Numbers
this quantum number defines the shape of the orbital
- allowed values of ranging 0 to n − 1
Azimuthal Quantum Number (l)
describes the three-dimensional orientation of the orbital
- values of integers ranging from -l to l
Magnetic Quantum Number (ml)
electrons in the same orbital do not have the same energy.
- upward or downward
Spin Quantum Number (ms)
sphere around the nucleus
1s orbital
the one that tells you that the electron is in the orbital closest to the nucleus
1s orbital
similar to 1s except the electron is most likely in the region farther from the nucleus
2s orbital
at the first energy level, there is only the 1s orbital, after the second energy level there are
2p orbitals
look like dumbells
p orbitals
distribution of all electrons in an atom
electron configurations
4p^5
what is 5?
superscript denoting the number of electrons in those orbitals
4p^5
what is p?
letter denoting the type of orbital
4p^5
what is 4?
number denoting the energy level
“For degenerate orbitals, the lowest energy is attained when the number of electrons with the same spin is maximized.”
Hund’s Rule
Filling Rules of Electron Orbitals
Electrons are added one at a time to the lowest energy orbitals available until all the electrons of the atom have been accounted for.
Aufbau Principle
Filling Rules for Electron Orbitals
An orbital can hold a maximum of two electrons, to occupy the same orbital, two electrons must spin in opposite directions
Pauli Exclusion Principle
Filling Rules for Electron Orbitals
Electrons occupy equal-energy orbitals so that a maximum number of unpaired electrons results.
Hund’s Rule
when n = 1?
what are the possible values of l, subshell designation, ml, numbers of orbitals in subshell, total numbers of orbitals?
l = 0
subshell designation = 1s
ml = 0
numbers of orbitals in shell = 1
total number of orbs = 1
when n = 2?
what are the possible values of l, subshell designation, ml, numbers of orbitals in subshell, total numbers of orbitals?
l = 0,1
subshell designation = 2s, 2p
ml = 0 1, 0 , -1
numbers of orbitals in shell = 1, 3
total number of orbs = 4
when n = 3?
what are the possible values of l, subshell designation, ml, numbers of orbitals in subshell, total numbers of orbitals?
l = 0,1,2
subshell designation = 3s 3p 3d
ml = 0 1, 0, -1 2, 1, 0, -1, -2
numbers of orbitals in shell = 1, 3, 5
total number of orbs = 9
when n = 4?
what are the possible values of l, subshell designation, ml, numbers of orbitals in subshell, total numbers of orbitals?
l = 0, 1, 2, 3
subshell designation = 4s 4p 4d 4f
ml = 0 1, 0, -1 2, 1, 0, -1, -2 3, 2, 1, 0, -1, -2, -3
numbers of orbitals in shell = 1, 3, 5, 7
total number of orbs = 16
It is the grouping of electrons that is not at the lowest possible energy state
Excited state
It is the grouping of electrons that is at the lowest possible energy state
Ground state
Atoms return to ground state by
emitting radiation
To understand the electronic structure of atoms, one must understand the nature of
electromagnetic radiation
The number of waves passing a given point per unit of time is the
frequency (v)
For waves traveling at the same velocity, the _____the wavelength,
the ______the frequency
longer , smaller
in, E = hv, what is h?
Planck’s constant (6.626 x 10 J*s)
One does not observe a continuous
spectrum, as one gets from a white light source.
Only a line spectrum of discrete wavelengths is observed.
developed a mathematical treatment into which both the wave and particle nature of matter could be incorporated.
Erwin Schrödinger
quantum mechanics
is the amount of energy needed to move from one energy level to another
quantum
The wave equation is designated with a
lower case Greek psi ()
gives a probability density map of where an electron has a certain statistical likelihood of being at any given instant in time
square of the wave equation, 2
- Describes the three-dimensional orientation of the orbital
Magnetic Quantum Number, ml
Distribution of Electrons
No two electrons in the same atom can have exactly the same energy
Pauli Exclusion Principle
no two electrons in the same atom can have identical sets of .
quantum numbers
Distribution of Electrons
Electrons occupy the positions of the lowest energy
Aufbau Principle
Distribution of Electrons
Electrons in the same sublevel occupy empty orbitals rather than pair up
Hund’s Rule
no two electrons in an atom have the same four quantum number’s
Pauli exclusion principle
Electrons are added one at a time to the lowest energy orbitals available until all the electrons of the atom have been accounted for.
Aufbau Principle
An orbital can hold a maximum of two electrons.To occupy the same orbital, two electrons must spin in opposite directions.
Type of principle
Pauli Exclusion Principle
Electrons occupy equal-energy orbitals so that a maximum number of unpaired electrons results.
Hund’s Rule
Electrons behave as
particle and wave
describes the probability of the location of the electrons
Shapes and Orientations of Orbitals
are useful way of the describing the elements.
Electronic Configuration
adopted Planck’s assumption and explained these phenomena in this way
Niels Bohr
The Nature of Energy
- Electrons in an atom can only occupy certain orbits
- Electrons in permitted orbits have specific, “allowed” energies; these energies will not be radiated from the atom.
- Energy is only absorbed or emitted in such a way as to move an electron from one “allowed” energy state to another; the energy is defined by E = hv
RH is the
Rydberg constant, 2.18 x 10^−18 J
posited that if light can have material properties, the matter should exhibit wave properties.
Louis de Broglie
Louis de Broglie demonstrated that the relationship between mass and wavelength was
λ =h/mv
Chromium can be detected in atomic absorption spectroscopy by
monitoring the absorbance of UV light at a wavelength of 357.8 nm
➢ What is the energy of a photon of this light?
replaced the Bohr model of the atom
Quantum mechanical model
Quantum mechanical model depicts electrons as waves spread out or delocalized through a region of space called
orbital
Wave behavior was described using a wave function, called as the
Schrödinger equation
