Electronic Structure (PHY, GC) Flashcards
The electrons closer to the nucleus are at ___ energy levels, while those that are further out (in higher electron shells) have ____ energy.
lower, higher
Valence electrons have the ___ interactions with the surrounding environment and the ____ interactions with the nucleus.
strongest, weakest
Valence electrons are much more likely to become involved in bonds with other atoms because they experience the ___ electrostatic pull from their own ____.
least, nucleus
A positively charged ion
cation
A negatively charged ion
anion
The atomic mass of an atom (in amu) is nearly equal to the _____, which is the sum of the protons and neutrons
mass number
Atoms of the same element with varying mass numbers are called
isotopes
Isotopes differ in their number of ___
neutrons
Atomic weight
The weighted average of the different isotopes and is the number reported on the periodic table
Avogadro’s number
6.02 x 10 ^ 23
What does Avagadro’s Number represent?
The number of “things” (atoms, ions, molecules) in 1 mole
As electrons go from a lower energy level to a higher energy level, they get AHED
A: absorb light
H: higher potential
E: excited
D: distant (from nucleus)
When an electron returns to ground state,
it emits a photon with wavelength of energy it undergoes
The electromagnetic energy of photons equation
E = hc/λ where h = Planck's constant c = speed of light (3.0 x 10^8 m/s) λ = wavelength of radiation
The energy of the emitted photon corresponds to the difference in energy between the _____-energy ___ state and the ___-energy ___ state
higher-energy initial state, lower-energy final state
a positive E corresponds to ___ and a negative E corresponds to ____
(+) E = emission
(-) E = absorption
According to the Pauli Exclusion Principle,
no 2 electrons in a given atom can possess the same set of 4 quantum numbers
Heisenberg Uncertainty Principle
It is impossible to simultaneously determine, with perfect accuracy, the momentum and the position of an electron
The principle quantum number, n: the larger the integer value of n, the ____ the energy level and radius of the electron’s shell
higher
Maximum number of electrons within a shell (equation)
2n^2
The difference in energy between two shells ____ as the distance from the nucleus increases
decreases
angular momentum, l
refers to the shape and number of subshells
value of l ranges from 0 to (n-1)
l = 0 subshell is _ l = 1 subshell is _ l = 2 subshell is _ l = 3 subshell is _
s, p, d, f
Maximum number of electrons within a subshell (equation)
4l +2
magnetic quantum number, ml
specifies the particular orbital within a subshell where an electron is most likely to be found at a given moment in time.
each orbital can hold a maximum of ___ electrons
two
The possible values of ml are the integers between ___ and ___, including 0
-l and +l
spin quantum number, ms
two spin orientations designated by +1/2 and -1/2
Whenever two electrons are in the same orbital, they must have ____ spins
opposite
Every element has a ____ atomic absorption and emission line spectrum
unique
An _______ is the pattern of line formed when a light passes through a prism to separate it into the different frequencies of light it contains
- each of these spectral lines corresponds to a different electron transition from a ___ energy state to a ___ energy state
atomic emission spectrum
- higher, lower
The n+l rule, used to rank subshells by ____ energy.
increasing
This rule states that the lower the sum of the values of the first and second quantum numbers, n + l, the lower the energy of the subshell.
–> if 2 subshells possess the same n+l value, the subshell with the lower n value has a lower energy and will fill with electrons first.
The n+l rule in action,
Which will fill first, the 5d subshell or the 6s subshell?
The 6s will fill first
5d: n=5 + l=2 = 7
6s: n=6 + l=0 = 6
The lowest s subshell is __, the lowest p subshell is __, the lowest d subshell is ___, and the lowest f subshell is ___
1s, 2p, 3d, 4f
What is the electron configuration of osmium (Z = 76)?
*use noble gas abbreviation
[Xe]6s24f145d6
What is the electron configuration of Fe3+?
[Ar]3d5
Hund’s rule tells us that ___ and ___ orbitals have ___ energies (___ stability) than other states
half-filled, fully filled, lower energies, higher stability
Hund’s rule creates 2 notable exceptions to electron configuration, chromium (and the other elements in its group) and copper (and the other elements in its group). What are the electron configurations of Chromium (Z=24) and Copper (Z=29)?
Chromium: [Ar]4s13d5
Copper: [Ar]4s13d10
Paramagnetic of diamagnetic?
Materials composed of atoms with unpaired electrons will orient their spins in alignment with a magnetic field, thus be weakly attracted to the magnetic field
paramagnetic
–> mnemonic:
PARAmagnetic means that a magnetic field with cause PARAllel spins in unpaired electrons and thus cause an attraction
Paramagnetic or diamagnetic?
Materials consisting of atoms that have only paired electrons will be slightly repelled by a magnetic field
diamagnetic
The ____ ____ of an atom are those electrons that are in its _____ energy shell, are ____ ____ removed, and are available for _____.
valence electrons, outermost, most easily, bonding
All elements in period ____ (starting with ___) and below may accept electrons into their d subshell, which allows them to hold more than eight electrons in their valence shell –> this allows them to violate the ___ ____.
three, sodium, octet rule
The ____ is the net positive charge experienced by an electron in a multi-electron atom.
effective nuclear charge (Zeff)
The _____ describes the ___ in the attraction between an electron and the nucleus in any atom with more than 1 electron shell.
shielding effect, decrease
The more electron shells there are, the __ the shielding effect experienced by the outermost electrons.
greater
The effective nuclear charge on an electron is given by the following equation:
Zeff = Z-S
Z is the number of protons in the nucleus (atomic #)
S is the number of electron between the nucleus and the electron in question (the number of non-valence electrons)
The shielding effect explains why ____ electrons are ______ removed from the atom
valence-shell, more easily
When light strikes materials, it can ____ electrons from them. This is called the ____ _____.
eject. photoelectric effect
In the photoelectric effect, electrons are ____ from matter as a consequence of their _____ from electromagnetic radiation of high frequency (_____ wavelength), such as UV radiation.
emitted, absorption of energy, short
If the energy of the light is such that the electron is ___ above ____ associated with the atom, the electron can break free from the atom leading to ____ of the atom. These escaping electrons are called ___.
excited, energy levels, ionization, photons
Energy of a photon equation:
E = hf
h is Planck’s constant
f is the frequency of EM wave
The energy required to knock off an electron is called the _____.
Ionization energy
