Chem I: 1-6 Flashcards
atomic number
(Z) number of protons
mass number
- (A) total number of protons and neutrons in nucleus
- Z+N
- aka atomic mass
isotopes
atoms that share an atomic number but have different mass numbers (same number of protons, diff number of neurons)
valence electrons
- electrons that are farthest from nucleus
- electrons that have the greatest amount of potential energy (bc they are held less tightly by the nucleus)
cation
positively charged aton
anion
negatively charged atom
isotopes are referred to…
by the name of the element followed by the mass number
atomic weight
- weighted average of the naturally occurring isotopes
- mass of one mole of the element in grams
binding energy
- energy required to disassemble an atom into its constituents
- allows nucleons to bind together in nucleus
mass defect
- the difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons
- result of matter that has been converted to energy
number of protons and electrons in neutral atom
of protons = # of electrons
Einstein’s equation that relates energy and mass (+ units)
E = mc^2 converts mass and energy
E in J
m in kg > mass defect
c in m/s
E in E = mc^2
energy released when the nucleus of an atom is formed (nuclear binding energy) and energy needed to break nucleus apart
nuclear binding energy
- the energy released when a nucleus is formed from nucleons
- energy required to disassemble an atom into its constituents
nucleons
protons and neutrons in the nucleus
electrostatic force
force between electrically charged objects (like charges repel and opposite charges attract each other).
nuclear strong force
- force that overcomes repulsion of the protons in nucleus to hold the nucleus together
- only acts over extremely short distances
N/Z ratio when Z < 20
N/Z = 1 –> stable nucleus
N/Z ratio when Z > 20
N/Z = 1.5 –> stable nucleus
N/Z ratio when Z > 83
p much all nuclei are unstable
alpha decay
ejection of an alpha particle (He) from the nucleus of an atom
beta decay
- ejection of a beta particle (electron) from the nucleus of an atom
- neutron converted to proton and electron
gamma decay
- release of gamma rays (no charge and no mass) from a nucleus
- energy is released in form of radiation
positron emission aka positive beta decay
a proton decays and “creates” a neutron
what increases the rate of radioactive decay?
- more protons in nucleus = more unstable = more decay
- for smaller atoms, the N/Z ratio determines stability (1:1)
half life
time required for a certain amount of pure substance to fall to half its original amount
what makes atom more likely to undergo alpha decay?
large number of protons in nucleus
electron capture
atom captures and electron and combines it with a proton to form a neutron
half life equation
t1/2 = 0.693/k
ionizing radiation
the release of energy that allows an unstable nucleus to attain a more stable form
how does the mass defect relate to the binding energy?
- there is a transformation of nuclear matter to energy with a resultant loss of matter
- mass defect - energy released
- binding energy - energy needed
- they are related by E = mc^2
fusion
when small nuclei combine to form a larger nucleus
fission
- large nucleus splits into smaller nuclei
- can occur through absorption of low energy neutron –> making an excited state
T/F: Nuclear fission and nuclear fusion both release energy
TRUE
Which type of nuclear decay could be detected in an atomic absorption spectrum?
because gamma radiation produces electromagnetic radiation (rather than nuclear fragments), it can be detected on an atomic absorption spectrum.
isotope notation
avogadro’s number
multiplying
6.02 x 10^23 atoms/mol
number of atoms/molecules in a mole
multiplying Avogadro’s number by the moles of an element gives the number of atoms of that element.
equation relating energy and frequency
E = hf
equation
angular momentum of an electrno orbiting a hydrogen nucleus
L = nh / 2π
n = principal quantum number
how will protium behave in an electric field as compared with deuterium?
a) protium will accelerate slower than deuterium
b) neither protium nor deuterium will accelerate
c) protium will accelerate faster than deuterium
d) protium and deuterium will both accelerate at the same rate
b) neither protium nor deuterium will accelerate
only charged particles experience force due to an electric field
since they are both neutral, neither will be influenced by electric field
Phosphorus has 2 known isotopes that weigh 30 amu (90% abundance) and 31 amu (10% abundance). What is the most likely atomic mass of a single Phosphorus atom?
a) 30.1 amu
b) 31 amu
c) 30 amu
d) 30.9 amu
Atomic mass of a single atom is a discrete whole number based on the number of nucleons found in a single atom. The most abundant isotope is made of 30 nucleons, thus the most likely atomic mass of an individual atom is 30 amu.
Nuclei (Z < 20) with N/Z ratio greater than one can undergo __________.
beta decay
Nuclei (Z < 20) with N/Z ratio less than one can undergo _________.
positron emission
Phosphorus-32 is commonly used to label DNA and RNA for
use in Southern and Northern blots, respectively. A
researcher has a 70 g sample of Phosphorus-32 stored for
future use. If the researcher needs at least 10 g of
Phosphorus-32 to do his experiment, what’s the greatest
number of days that he could store this sample? (Phosphorus-
32 has a half-life of 14.3 days)
a) 25 days
b) 45 days
c) 30 days
d) 40 days
d) 40 days
A radioactive sample is giving off gamma rays. What is occurring on the atomic scale?
a) a nucleus in an excited state releases a photon, becoming a new element in its ground state
b) a nucleus in an excited state releases a photon, going to its ground state
c) a nucleus in its ground state releases a photon, becoming a new element in its ground state
d) a nucleus in its ground state releases a photon and remains in its ground state
b) a nucleus in an excited state releases a photon, going to its ground state
In gamma decay, nucleus is in unstable high energy state. It releases this energy by emitting a photon, going to more stable ground state.
A researcher adds 5g of NaCl to a beaker containing 120 g of water. How many water molecules are present?
a) 4 x 10^24
b) 7.2 x 10^21
c) 6 x 10^23
d) 1.3 x 10^24
a) 4 x 10^24
a) emission spectrum with dark lines where hydrogen is emitting light
b) absorption spectrum with dark lines where hydrogen is absorbing light
c) an emission spectrum with bright lines where hydrogen is emitting light
d) an absorption spectrum with bright lines where hydrogen is absorbing light
mass to charge ratio
The mass of an ion divided by its charge
symbol m/z
purpose of mass spectrometer
determine the mass of a particle using electric and magnetic fields
how the mass spectrometer works
- the movement of excited (ionized) particles will be affected as they pass through a magnetic field
- the degree to which these particles are deflected from their original path will depend on their mass/charge
large vs small particles in mass spectrometer
- large particles travel with a larger radius and slower acceleration -> travels longer distance than smaller particle
- smaller particle -> greater centripetal acceleration –> smaller radius
mass spectra
plot of relative abundance (y plane) vs mass to charge ratio (x plane)
Mass Spectrometry: if the charge on the ion is +1, the mass to charge ratio is…..
if the charge on the ion is +1, the mass to charge ratio is equal to the mass of that ion
Mass Spectrometry: relative abundance
the intensity of the ion as it collides with ion detector
Mass Spectrometry: p+1 peak
the molecule that contains heavier isotopes
Mass Spectrometry: fragmentation pattern
lower weight molecules that are fragments the og molecule
Mass Spectrometry: base peak
- the highest peak, which may or may not correspond to the parent ion
- the base peak is always made equal to 100% relative abundance
photoelectric effect
emission of electrons from a metal when light shines on the metal
Photoelectric effect equation
E = hv= hc/lambda
frequency related to wavelength equation
c = lambda * v
lambda = wavelength
photoelectric effect: if shining light on an electron does not excite that electron to a new energy state, what will increasing the intensity of light do?
- intensity is the same as amount
- it will have no effect on the electron
photoelectric effect: if shining light on an electron does not excite that electron to a new energy state, what will increasing the frequency of light do?
- the light particle has more energy when the frequency increases (deltaE = hf)
- the electron has the possibility of being excited to a higher state
Coulomb’s Law
- (bohr model) electric force between charged objects depends on the distance between the objects and the magnitude of the charges
- (electrons get neg sign)
force equation
F=ma (force = mass x acceleration)
the bohr model predicts…
the wavelength of light emitted by the hydrogen atom
binding energy per nucleon peaks at the element ___, which implies that…
iron
iron contains the most stable nucleus
weak nuclear force
- also contributes to stability of nucleus
- much weaker than strong nuclear force
4 fundamental forces of nature
strong nuclear force, weak nuclear force, gravitation, electrostatic forces
electrons are emitted by the nucleus when…
a nutron decays into a proton (a beta particle)
exponential decay (half life)
exponential decay equation
bohr model rules
- electrons move about nucleus in circular orbit and each orbit corresponds to a discrete quantity of energy
- electrons emit energy only when an electron moves from a higher orbit to a lower orbit
to calculate how much energy an electron loses in bohr model
Ehigher - Elower = Ephoton = hf
what happens when an electron moves from higher stationary state to a lower state?
releases a single photon of light
ionization energy
- the energy required to remove an electron from a gaseous species
- cation now has more energy than neutral atom -> less stable
- the less likely an atom gives up an electron, the more energy required to take that electron away
- energy is put in to remove electron
- positive energy
- endothermic process
- F = Kq1q2 / r2
absorption
electron absorbs energy and jumps up to higher energy level
emission
when an electron falls from a higher energy level to a lower energy level, and a photon is emitted
the energy of the electron changes in discrete amounts with respect to…
energy is directly proportional to principal quantum number
bohr model: electron in any of its quantized states in the atom will have an attractive force towards….
the proton
as the energy of an electron increases (becomes ____)…
(becomes less negative)… the farther out from the nucleus that it is located (increasing n in eq)
as electrons go from a lower energy level to a higher energy level, they get…
AHED
absorb light, higher potential, excited, distant (from nucleus)
current
net charge flow per unit time
threshold frequency
- minimum frequency of light that causes ejection of electrons
- depends on type of metal being exposed to the radiation
if the frequency of the incident photon is less than the threshold frequency….
then no electron will be ejected because the photons do not have sufficient energy to dislodge the electron from the atom
waves with higher frequency have… (wavelengths, energy, light spectrum)
shorter wavelengths and higher energy (toward blue and UV end of spectrum)
waves with lower frequency have… (wavelengths, energy, light spectrum)
longer wavelengths and lower energy (toward red and infrared end of spectrum)
if the frequency of an incident photon is above the threshold frequency of a metal, the photon…
will have more than enough energy to eject a single electron, and the excess energy will be converted to kinetic energy in the ejected electron
maximum kinetic energy formula
Kmax = hf - W
work function
minimum energy required to eject electron (similar to activation energy)
work function related to frquency of metal formula
W = hfthreshold
what does the threshold frequency depend upon?
the chemical composition of the material
what electrical phenomenon results from the application of the photoelectric effect?
the accumulation of moving electrons creates a current during the photoelectric effect
ground state of an atom
state of lowest energy, in which all electrons are in the lowest possible orbitals
excited state of an atom
when at least one electron has moved to a subshell of higher than normal energy
when electrons return to their ground states…
each will emit a photon with a wavelength characteristic of the specific energy transition it undergoes
line spectrum
each line on the emission spectrum corresponds to a specific electron transition
lyman series
group of hydrogen emission lines corresponding to transitions from energy levels n ≥ 2 to n=1
balmer series
corresponds to transitions from energy levels n ≥ 3 to n=2
lyman vs balmer series
- lyman series includes larger energy trnasitions
- shorter photon wavelengths in UV region
paschen series
corresponds to transitions from n≥4 to n=3
equation that says: the energy of the emitted photon corresponds to the difference in the energy between the higher energy initial state and the lower energy final state
photoelectric effect: the higher the intensity of the light beam…
the greater the number of photons per unit time that fall on an electrode, producing a greater number of electrons per unit time liberated from the metal
photoelectric effect: when the light’s frequency is above the threshold frequency…
the magnitude of the resulting current is direction proportional to the intensity and amplitude of the light beam
if the frequency of a photon of light incident on a metal is at the threshold frequency for the metal…
the electron barely escapes from the metal
Kmax is only achieved when…
all possible energy from the photon is transferred to the ejected electron
how does the work function relate to the energy necessary to emit an electron from a metal?
- work function describes the minimum amount of energy necessary to emit an electron
- any additional energy from a photon will be converted to excess kinetic energy during photoelectric effect
electric potential energy
bohr model
q1 = charge on electron
q2 = charge on nucleus
potential energy of electron in ground state
negative potential energy
What is the equation for magnetic force in terms of magnetic field strength and velocity of an ion?
F = qvB
F = Magnetic Force q = Charge of ion V = Velocity of ion B = Magnetic Field Strength
In a mass spectrometer, the ion moves in a circle. Why?
The ion moves in a circle because the magnetic force is perpendicular to the velocity of the ion, pointing toward the center of the circle. The magnetic force essentially acts as a centripetal force.
Which equation can be used in tandem with F = qvB in order to calculate the mass of an ion in a mass spectrometer based on the radius of the circle?
Fc = m(v^2/r)
What is the resulting equation when everything is set equal to r?
r = mv/qB
The energy of the photon is greater than, equal to, or less than the energy of the emitted electron? Why?
The energy of the photon is greater than the energy of the emitted electron. This is because some of the energy of the photon was required (and used up) in order to free the electron from the metallic surface.
What is the equation for the energy of a photon in terms of the energy of the emitted electron?
KEp = KEe + WF
KEp = Kinetic energy of the photon KEe = Kinetic energy of the electron WF = Work function
A metal has a work function equal to 3.42 ⋅ 10^-19 J and the energy of the electron is equal to 3.47 ⋅ 10^-19 J. What is the frequency of the photon? (remember Plank’s constant = 6.626 ⋅ 10^-34).
(A) 3.04 ⋅ 10 ^ -19 Hz
(B) 6.02 ⋅ 10 ^ -13 Hz
(C) 8.06 ⋅ 10 ^ 12 Hz
(D) 1.15 ⋅ 10 ^ 15 Hz
D) 1.15 ⋅ 10 ^ 15 Hz
KEp = KEe + WF
KEp = 3.47 ⋅ 10^-19 J + 3.42 ⋅ 10^-19 J
KEp = 6.89 ⋅ 10^-19 J
hv = KEp
(6.626 ⋅ 10^-34)v = 6.89 ⋅ 10^-19 J
v = (7 ⋅ 10^-19)/(6 ⋅ 10^-34)
v = about 1 ⋅ 10^15 hz (Actual 1.15 ⋅ 10^15 hz)
Which physics equation relates the energy of a photon to its frequency?
E = hf
E = Energy of a photon or quantum h = Planck's Constant (6.626 ⋅ 10^-34 J⋅s) f = Frequency of wave/radiation
What two equations can be used in concert with Fc = m(v^2/r) to determine the radius of a Bohr model electron?
Fe = k((q1q2)/r^2) and L = rp
An electron’s total energy is composed of what two types of energy?
(A) Thermal and kinetic energy
(B) Kinetic and electric energy
(C) Electric and potential energy
(D) Thermal and electric energy
(B) Kinetic and electric energy
An electron’s total energy is composed of kinetic and electric energy.
What equation can be used to determine the energy of any electron in terms of its principal quantum number?
En = E1/(n^2)
En = Energy of electron at n n = Principal quantum number E1 = Energy of electron at n=1 (-2.17 ⋅ 10^-18 J)
The energy at the first orbital is equal to -2.17 ⋅ 10^-18 J. What is the energy in terms of electron-volts (eV)?
(A) 19.2 eV
(B) 3.7 eV
(C) -1.4 eV
(D) -13.6 eV
(D) -13.6 eV
(-2.17 ⋅ 10^-18 J) / (1.6 ⋅ 10^-19) = approximately -10 eV (actual: -13.6 eV)
The energy at the first orbital is equal to -13.6 eV. What is the energy in terms of electron-volts (eV) of an electron in the third orbital?
(A) -9.6 eV
(B) -4.8 eV
(C) -3.4 eV
(D) -1.5 eV
(D) -1.5 eV
En = E1/(n^2) E3 = -13.6 eV / 3^2 E3 = approx. -1.5 eV
An electron drops from the second orbital to the first orbital (-13.6 eV). A photon with how much energy is given off?
(A) -9.6 eV
(B) 6.3 eV
(C) 10.2 eV
(D) 13.6 eV
(C) 10.2 eV
En = E1/(n^2) E2 = -13.6 eV / 2^2 E2 = approx. -3 eV
E1 - E2 = -13.6 eV - (-3eV) = -10.6 eV from the electron, so the photon has an energy of approx. 10.6 eV (actual: 10.2 eV)
What does it mean in terms of energy levels of electrons to say that the ionization energy of an atom is -13.6 eV?
It would require 13.6 eV to move an electron from n=1 to n=infinity, making the Hydrogen atom an ion.
Ernest Rutherford conducted an experiment in which he fired alpha particles at gold foil. He noticed that the majority of alpha particles were not deflected by the gold foil, and all alpha particles would exit the foil. What did these results reveal about an atom’s structure?
The Rutherford experiments concluded that an atom has a dense, positively charged nucleus taking up a small fraction of an atom’s volume.
Based on the previous description of the Bohr model, which of the following atoms does not represent the Bohr model?
(A) H
(B) He+
(C) Li+
(D) Be 3+
The Bohr model relies upon there being only a single electron. Li+ has two electrons, whereas all other options have only one electron.
True or false? The Rydberg unit of energy is equal to 2.18 ⋅ 10 ^-18 J/electron, and is the experimentally determined energy of an electron at the smallest possible orbital.
True. The Rydberg unit of energy is equal to 2.18 ⋅ 10 ^-18 J/electron, and is the experimentally determined energy of an electron at the smallest possible orbital.
a) 1:3:5
b) 1:1:1
c) 1:4:9
d) 1:2:4
c) 1:4:9
what happens during mass spectroscopy?
sample is bombarded with electrons in order to ionize the sample
ions are then subjected to both electric and magnetic fields
mass spectrometer separates ions based on…
mass to charge ratio
amount of deflection in mass spectrometer is ______ to mass to charge ratio
inversely propotional
how to tell which ions would be least deflected in mass spectrometer?
highest mass to charge ratio –> least deflected
Which of the following is NOT true of an electron returning to its ground state?
a) it emits photons
b) distance between nucleus and electron decreases as the electron returns to its ground state
c) releases energy
d) gains potential energy as it falls to the ground level
d) gains potential energy as it falls to the ground level
according to the bohr model, which of the following transitions of an electron produce a photon with the lowest energy?
a) n=3 to n=4
b) n=4 to n=3
c) n=4 to n=2
d) n=2 to n=4
b) n=4 to n=3
a) 0
b) 360
c) 120
d) 60
a) 0
all of the following statements are false about photoelectric effect EXCEPT?
a) kinetic energy of the emitted electron depends on the frequency of the photon and work function of the metal
b) energy of the incident photon is inversely proportional to its freq
c) number of electrons emitted depends only on the frequency of the incident photons
d) energy of the incident photon is directly proportion to its wavelength
a) kinetic energy of the emitted electron depends on the frequency of the photon and work function of the metal
a) inc the wavelength of photons
b) inc the number of photons
c) inc the freq of photons
d) dec the freq of photons
b) inc the number of photons
photoelectric affect
what affects the velocity of electrons?
- inc freq, inc energy, inc velocity
- inc wavelength, dec energy, dec velocity
a) red and violet
b) green and blue
c) violet and red
d) blue and green
a) red and violet
a) Be3+
b) He+
c) H
d) Li+
d) Li+
a) Each series specifies the wavelength emitted when an electron drops down a specific number of orbitals, decreasing by exactly one, two, or three orbitals, respectively.
b) Each series specifies the wavelengths emitted when an electron drops from higher energy levels to the first, second, and third energy level, respectively.
c) Each series specifies the wavelength emitted when an electron drops down a specific number of orbitals, decreasing by exactly two, three, or four orbitals,
respectively.
d) Each series specifies the wavelengths emitted when an electron drops from a higher energy level to the second, third, and fourth energy level, respectively.
b) Each series specifies the wavelengths emitted when an electron drops from higher energy levels to the first, second, and third energy level, respectively.
a) n=2 to n=4
b) n=4 to n=2
c) n=3 to n=4
d) n=4 to n=3
b) n=4 to n=2
a) energy of electron is greater than the energy of the photon
b) energy of the electron is less than the energy of the photon
c) energy of electron is zero
d) energy of electron is the same as the energy of the photon
b) energy of the electron is less than the energy of the photon
a) n=1 to n=2
b) n=1 to n=0
c) n=infinity to n=1
d) n=1 to n=infinity
d) n=1 to n=infinity
a) 286 nm
b) 867 nm
c) 367 nm
d) 486 nm
a) 3.4 eV
b) -1.5 eV
c) -13.6 eV
d) 8 eV
b) -1.5 eV
a) electron energy dec since E1 is neg
b) electron energy inc since E1 is neg
c) electron energy inc since E1 is pos
d) electron energy dec since E1 is pos
b) electron energy inc since E1 is neg
a) KE is neg, PE is pos
b) KE is neg, PE is neg
c) KE is pos, PE is pos
d) KE is pos, PE is neg
d) KE is pos, PE is neg
a) 3/2
b) 4/9
c) 9/4
d) 2/3
b) 4/9
a) nitrogen
b) carbon
c) hydrogen
d) sulfur
d) sulfur
a) (mass x velocity) / (magnetic force)
b) (mass x acceleration) / (magnetic force)
c) (mass) x (velocity)^2 / (magnetic force)
d) (mass) x (acceleration)^2) / (magnetic force)
c) (mass) x (velocity)^2 / (magnetic force)
a) distance the ion traveled through the electric field
b) radius of the ion’s path in magnetic field
c) charge of the ion
d) size of the ion
b) radius of the ion’s path in magnetic field
heisenberg uncertainty principle
it is impossible to simultaneously determine, with perfect accuracy, the momentum and position of an electron
uncertainty principle eq (2)
p=mv, p = momentum
ΔxΔp ≥ h/4π
uncertainty principle
dec uncertain in position…
inc uncertainty in momentum
the uncertainty principle has nothing to do with…
the precision of the instrument we are using to measure
wave particle duality
matter on a subatomic level can act as particles and as waves
energy eq with lambda
Ephoton = hc/lambda
as principal quantum number (n) inc, the avg distance of electron ___
inc, atom is larger (radius), and energy inc
principal quantum number (n)
n = any positive integer
main energy level/shell
azithmuthal (angular momentum) quantum number (l)
designates the subshell where the electron is located
shape of the orbital –> most probable location of electrons
important implications for chemical bonding and bond angles
l = 0, 1, 2… n-1
l = 0 –> s orbital
magnetic quantum number (ml)
designates the exact orbital in which our electron is in -> direction of angular momentum
orientation
ml = -l to +l
spin quantum number (ms)
ms = +1/2 up
ms = -1/2 down
because orbitals can have a max of 2 electrons
pauli exclusion principle
any two electrons in a given atom cannot have the same 4 quantum numbers
number of total orbitals within a shell level (n) can be found using
n2
eq to calculate energy of electron using nth principle quantum number
En = Ei / n2
eq to calculate az quantum number (l) and angular momentum
L2 = h2l(l+1)
L = angular momentum
space quantization
any orbital has a certain number of orientations in space
where do you lose the electron from?
from the orbital that is highest in energy
hard part of writing electronic configurations
metals at Cr -> jumps to [Ar] 4s1 2d5 -> fills up d until
Cu -> [Ar] 4s1 3d10 -> fills up 4 and stays at 3d10
Aufbau Principle
electrons will fill orbitals from lowest to highest energy
hund’s rule
electrons are going to fill orbitals one at a time before doubling up
electron configuration periodic table
What is the electron configuration of osmium (Z=76)?
[Xe] 6s2 4f14 5d6
What is the electron configuration of Fe3+?
[Ar] 3d5
electrons are removed from the 4s subshell before the 3d because it has a higher principal quantum number
write out and compare an orbital diagram for a neutral oxygen atom and an O2- atom
- both have fully filled 1s and 2s orbitals
- O has 4 electrons in 2p
- 2 paired, other 2 have own orbital
- O2- has 6 electrons in 2p
- all are paired
where did the Bohr model fail?
- did not take into account the repulsion between multiple electrons surrounding the nucleus
- electrons do NOT follow a clearly defined circular pathway or orbit at a fixed distance from the nucleus
what do we know today about orbitals?
electrons move rapidly and are localized within regions of space around the nucleus called orbitals
if we want to assess the position of an electron…
the electron has to stop (removing its momentum)
energy state
the position and energy of an electron described by its quantum numbers
eq max number of electrons within a shell
2n2
eq max number of electrons within a subshell
4l + 2
as l values inc…. the energies of the subshell
increase
as atomic number inc, the number of electrons
also increases
label the groups on periodic table
label how many valence electrons in each
valence electrons
elements in period 3 (starting w Na) and below
may accept electrons into their d subshell
which allows them to hold more than 8 electrons in their valence shell
valence electrons
langthanide and actinide series
highest s and f subshells
valence electrons
groups IIIA - VIIIA (groups 13-18)
highest s and p subshells
valence electrons
groups IA and IIA
highest s subshell
Draw the shape of the d orbital(s) and f orbital(s).
d has 5 orientations
f has 7 orientations
what is the max number of electrons that can be found in the 3rd energy level?
a) 10
b) 8
c) 32
d) 18
d) 18
What is the max number of electrons in an atom that have the following set of quantum numbers?
n=5 l=3 ml=+2 ms=+1/2
a) 2
b) 14
c) 1
d) 6
c) 1
Which of the following subshells do electrons enter first?
a) 4p
b) 2d
c) 3d
d) 4s
d) 4s
What is the total number of orbitals for the subshell with quantum numbers n=5 and l=1?
a) 6
b) 5
c) 3
d) 7
c) 3
What is the azimuthal quantum number (l) for the orbital from which an electron is lost to form Na+1?
a) 3
b) 1
c) 0
d) 2
c) 0
chemical families of periodic table
a) I, II, III
b) I and III only
c) II and III only
d) II only
a) I, II, III
a) Hund’s rule
b) Aufbau Principle
c) Markovnikov’s rule
d) Pauli exclusions principle
d) Pauli exclusions principle
Which can hold more electrons, the n=2 shell or the l=2 subshell, and by how large a difference?
a) n=2 can hold 4 more electrons than l=2
b) l=2 can hold 2 more electrons than n=2
c) n=2 can hold 2 more electrons than l=2
d) l=2 can hold 4 more electrons than n=2
b) l=2 can hold 2 more electrons than n=2
how many electrons are in the n=3 energy level?
a) 8
b) 16
c) 18
d) 10
c) 18
An astrologer is observing the emission spectrum of a star to see what gases it contains. What does an emission spectrum look like?
a) a noncontinuous spectrum with bright lines at wavelengths where a gas emits light
b) a continuous spectrum with dark lines at wavelengths where a gas absorbs light
c) a noncontinuous spectrum with bright lines at wavelengths where a gas absorbs light
d) a continuous spectrum with dark lines at wavelengths where a gas emits light
a) a noncontinuous spectrum with bright lines at wavelengths where a gas emits light
Potassium reacts with chlorine to form KCl, an ionic compound. What is the electronic configuration of potassium in KCl?
a) [Ar] 4s2
b) [Ar] 4s13d2
c) [Ar] 4s1
d) [Ar]
d) [Ar]
Yttrium in its ground state has 39 electrons. Which set of quantum numbers is not possible for Yttrium?
a) 4, 3, -3, -1/2
b) 2, 2, 1, 1/2
c) 3, 1, 0, 1/2
d) 5, 0, 0, -1/2
b) 2, 2, 1, 1/2
a) has uncertainty of 2.6 x 10^-10 m
b) has uncertainty of at least 2.6 x 10^-11 m
c) has average value of 2.6 x 10^-11 m
d) has avg value of 2.6 x 10^-10 m
a) has uncertainty of 2.6 x 10^-10 m
a) 656 nm
b) 80 nm
c) 322 nm
d) 122 nm
d) 122 nm
a) light w a wavelength of 656 nm is emitted
b) light w a wavelength of less than 656 nm is emitted
c) light w a wavelength greater than 656 nm is emitted
d) light w a wavelength of 656 nm is absorbed
b) light w a wavelength of less than 656 nm is emitted
metalloids
- aka semimetals
- in between metals and nonmetals
- reactivities dependent on the elements with which they are reacting
as you go across periods to the right… atomic radius ____
decreases
more protons as you go across -> more electrons in outer shell also increases -> nucleus pulls outer shell electron in more than inner shell electrons shield
Zeft inc
electron shielding
- inner electrons shielding outer electron from positively charged nucleus
- protons in nucleus pull outer shell electron in -> inner shell electrons repels outer shell electron
- (outer electrons don’t shield)
electron affinity
- energy released when a gaseous species gains an electron
- adding electron to neutral atom
- gives off energy to form anion
- negative energy
- exothermic process
- ΔHrxn = negative
- but reported as positive number
adding an electron but EA ≥ 0
- adding energy in to force the electron to form the anion
- positive energy
- because atom does not have electron affinity
periodic trends
which has larger radius?
F or F-
F-
which has larger radius?
K or K+
K
chalcogens
- crucial for normal biological functions
- at high concentrations, many can be toxic or damaging (usually the heavier ones)
groups in periodic table that exhibit:
high reactivity to water
groups 1 and 2
groups in periodic table that exhibit:
negative oxidation states
almost all groups but most notably transition metals
groups in periodic table that exhibit:
multiple oxidation states
all groups but most notably transition metals
groups in periodic table that exhibit:
possess a full octet in the neutral state
noble gases
Which has a greater electron affinity: Lithium or Berylium? Why?
Lithium. This breaks the normal electron affinity trend because Berylium’s new electron will be added to a far away p orbital, which will experience more shielding than Lithium completing its s orbital.
Which has a greater electron affinity: Nitrogen or Carbon? Why?
Carbon. This breaks the normal electron affinity trend because Nitrogen’s new electron will be added to a p orbital with another electron, which increases the amount of repulsion that the new electron will experience.
balance
single displacement reaction
aka substitution reactions
C kicks out B
double displacement reaction
aka metathesis reaction
one of products is removed from the solution as a precipitate or gas or when two of the of species combine to form a weak electrolyte that remains undissociated in solution
combustion reactions
hydrocarbons are burned in presence of diatomic gas to form CO2 and H2O molecules
balance
redox
assign ox number
a) all of the above
b) 3rd ionization energy
c) 2nd ionization energy
d) 1st ionization energy
b) 3rd ionization energy
Which of the following has the highest ionic radii?
a) N3-
b) F-
c) Li+
d) C
a) N3-
Which of the following is TRUE about transition elements?
a) they cannot conduct electricity
b) they have varying oxidation states
c) they all have an incomplete d orbital
d) they are more electronegative than halogens
b) they have varying oxidation states
a) electron affinity, since both describe an energy change when the number of electrons is changed in an atom
b) electronegativity, since both describe qualitative changes in electron density
c) electronegativity, since both describe an energy change when the number of electrons is changed in an atom
d) electron affinity, since both describe qualitative changes in electron density
b) electronegativity, since both describe qualitative changes in electron density
a) no, iron is never seen at oxidation states higher than +3 due to hund’s rule
b) yes, iron is occasionally seen with a charge of +8, giving it the same electron configuration as Argon
c) yes, iron is occasionally seen with a charge of +6, giving it the same electron configuration as calcium
d) no, iron is only able to lose its highest s orbital electrons
c) yes, iron is occasionally seen with a charge of +6, giving it the same electron configuration as calcium
a) silicon can form covalent bonds using more than 8 electrons, like in the compound SiO4
b) helium is a noble gas and relatively inert, even though it only has 2 valence electrons
c) xenon can form covalent bonds using more than 8 electrons, like in the compound XeF6
d) nitrogen can form covalent bonds using more than 8 electrons, like in the compound NO3
d) nitrogen can form covalent bonds using more than 8 electrons, like in the compound NO3
a) add an ethanol subunit
b) reduce the concentration of crown ether
c) increase the concentration of crown ether
d) remove an ethanol subunit
d) remove an ethanol subunit
a) it would decrease by about 1
b) it would increase by about 1
c) it would stay the same
d) it cannot be determined
b) it would increase by about 1
a) At
b) F
c) Li
d) Cs
d) Cs
a) He
b) Br
c) Mg
d) Rb
a) He
a) K+ > Na+ > Cl- > Ar
b) K+ > Cl- > Ar > Na+
c) Cl- > Ar > K+ > Na+
d) Na+ > K+ > Ar > Cl-
c) Cl- > Ar > K+ > Na+
which of the following classifications of elements is least conductive?
a) transition metals
b) metalloids
c) alkali metals
d) alkaline earth metals
b) metalloids
the elements fall into 3 broad categories: metals, metalloids, and nonmetals. which of the following groups contains exactly one nonmetal?
a) 1
b) 5
c) 9
d) 2
a) 1
a) they are all alkaline earth metals
b) they are all alkali metals
c) they are all transition metals
d) they are all metalloids
b) they are all alkali metals
a) Ca
b) Sr
c) Ba
d) Mg
c) Ba
bond polarity is important for understanding the interactions of molecules. which of the following would have the least polar bond?
a) F-N
b) Na-Cl
c) B-H
d) Cl-P
c) B-H
a) with the hydrogens closer to the ion, bc oxygen is more electronegative than hydrogen
b) with the hydrogens closer to the ion, bc hydrogen is more electronegative than hydrogen
c) with the oxygen closer to the ion, bc oxygen is more electronegative than oxygen
d) with the oxygen closer to the ion, bc hydrogen is more electronegative than oxygen
c) with the oxygen closer to the ion, bc oxygen is more electronegative than oxygen
a student wants to make a permanent magnet, and is learning about paramagnetic and diamagnetic materials. which material would make a better magnet?
a) neither
b) both
c) diagmagnetic
d) paramagnetic
a) neither
a student is surprised to learn that the acidity of a compound depends on how well an atom can accommodate a negative charge. how does this relate to electronegativity’s trends of increasing moving up and to the right?
a) Acidity will have the same trends because electronegativity depends on Z(eff), which increases as you move up and to the right on the periodic table.
b) Acidity will have the same trends because electronegativity is how much an element wants a negative charge, and donating the proton gives it a negative charge.
c) Acidity will not have the same trends as electronegativity.
d) Acidity will have the same trends because electronegativity increases as atomic radius decreases, and a smaller radius will allow a more delocalized negative charge, providing more stability.
c) Acidity will not have the same trends as electronegativity.
Reactions between metals and nonmetals are often
extremely exothermic, since both elements gain stability
by moving closer to the octet rule. Which of the following
would not be an example of this scenario?
a) boron and nitrogen
b) aluminum and phosphorus
c) radium and polonium
d) rubidium and astatine
a) boron and nitrogen
How many grams of calcium chloride are needed to prepare 71.7 g of silver chloride according to the following equation?
CaCl + 2 AgNO3 –> Ca(NO3)2 + 2 AgCl
Example: If 27.9 g of Fe react with 24.1 g of S to produce FeS, what would be the limiting reagent? How many grams of excess reagent would be present in the vessel at the end of the reaction?
Fe + S –> FeS
What is the percent yield for a reaction in which 28 g of Cu is produced by reacting 32.7 g of n in excess CuSO, solution?
The balanced equation is as follows:
Zn (s) + CuSO4 (aq) –> Cu (s) + ZnSO4 (aq)
A sample is assayed for lead by a redox titration with I3- (ag). A 10.00 g sample is crushed, dissolved in sulfuric acid, and passed over a reducing agent so that all the lead is in the form Pb2+. The Pb2+ (aq) is completely oxidized to Pb4+ by 32.60 mL of a 0.7 M solution of NaI3.
The balanced equation for the reaction is:
I3- + (aq) + Pb2+ (aq) –> Pb4+ (aq) + 3 I- (ag)
Calculate the mass of lead in the sample.
How is the formal charge of Chlorine changing in this hypothetical reaction: Li(s) + Cu(s) + OCl- -> CuO + LiCl?
(A) Chlorine goes from a -1 to a +1 formal charge
(B) Chlorine goes from a +1 to a -1 formal charge
(C) Chlorine goes from a 0 to a -1 formal charge
(D) Chlorine does not change, staying at a -1 formal charge
(C) Chlorine goes from a 0 to a -1 formal charge
Li(s) + Cu(s) + OCl- -> CuO + LiCl
Chlorine’s formal charge goes from 0 to -1.
We know that Chlorine starts out at a neutral formal charge based on the Lewis dot structure of Hypochlorite and how we calculate formal charges.
We also know that Chlorine has a -1 formal charge in LiCl because of the nature of that ionic bond.
from the electronic configurations given below, which element is most likely to act as an oxidizing agent?
a) [Ne]3s1
b) [Ar]4s23d104p6
c) [Ar]4s23d10
d) [Ne]3d9
d) [Ne]3d9
Some bacteria can oxidize sulfur to sulfuric acid and sulfite depending on the environmental conditions. What is the role of oxygen in these reactions?
a) it acts as a reducing agent
b) it loses electrons
c) it makes the reactions go faster
d) it acts as an oxidizing agent
d) it acts as an oxidizing agent
What is the ox number of chlorine in sodium hypochlorite (NaClO)?
a) +2
b) +1
c) -1
d) 0
b) +1
a) none of the above
b) I only
c) II and III only
d) III only
a) none of the above
MnO4- reacts with I- to form I2 and Mn2+ in a basic solution. What is the balanced eq for this reaction?
a) 2 MnO4- + 10 I- + 16 OH- –> 5 I2 + 2 Mn2+ + 8 H2O
b) 2 MnO4- + 10 I- + 16 H<span>+</span> –> 5 I2 + 2 Mn2+ + 8 H2O
c) 2 MnO4- + 10 I- + 8 H2O –> 5 I2 + 2 Mn2+ + 16 H+
d) 2 MnO4- + 10 I- + 8 H2O –> 5 I2 + 2 Mn2+ + 16 OH-
d) 2 MnO4- + 10 I- + 8 H2O –> 5 I2 + 2 Mn2+ + 16 OH-
Acid-base reactions are often also redox reactions. MnO4- reacts with I- in an acidic solution to form I2, and Mn2+. What is the ratio of H+ to I- used up by this reaction?
a) 1.6
b) 0.6
c) 0
d) 1
a) 1.6
Two aldehydes can react with each other to form an alcohol and a carboxylic acid. This is an example of a:
a) acid base rxn
b) elimination rxn
c) combustion rxn
d) disproportionate rxn
d) disproportionate rxn
What are the ox number of oxygen in OF2 and ClO2-?
a) -2 and -2
b) +2 and -2
c) -2 and +1
d) +1 and -2
b) +2 and -2
A student is trying to test the conductivity of different solvents, preparing for a big experiment. They are testing deionized water and pure diethyl ether as their two solvents. Which solution(s) will work well as a conductor in this experiment?
a) Both diethyl ether and deionized water will be good
conductors, since they are both polar.
b) Deionized water will be a better conductor, since it is more polar than diethyl ether.
c) Neither deionized water nor diethyl ether will be good conductors, since they both lack electrolytes.
d) Diethyl ether will be a better conductor, since it is less polar than deionized water.
c) Neither deionized water nor diethyl ether will be good conductors, since they both lack electrolytes.
Although the law of conservation of matter says that mass remains constant in a chemical reaction, those masses are free to move. Which of the following can be changed in a chemical reaction?
a) atom’s mass number
b) atom’s electron affinity
c) atom’s polarizability
d) atom’s oxidation state
d) atom’s oxidation state
What are the empirical and molecular formulas of a carbohydrate that contains 40.9% carbon, 4.58% hydrogen, and 54.52% oxygen and has a molar mass of 264 g/mol?
classify the most likely reactions
how many sulfur atoms exist in 3 moles of sulfur dioxide?
a) 6 x 10^23 atoms
b) 1.2 x 10^24 atoms
c) 1.8 x 10^23 atoms
d) 1.8 x 10^24 toms
d) 1.8 x 10^24 toms
how many moles are equal to 4.084 x 10^26 molecules?
a) 67.8 x 10^24 moles
b) 678 moles
c) 67.8 moles
d) 6.78 x 10^23 moles
b) 678 moles
How many sodium ions are present in 316 g of sodium phosphate, Na3PO4?
a) 3.6 x 10^23
b) 3.5 x 10^24
c) 6.6 x 10^23
d) 6.6 x 10^24
b) 3.5 x 10^24
a) 15.2 g
b) 26.4 g
c) 82.1 g
d) 57.6 g
b) 26.4 g
a) I and III only
b) I and II only
c) II and III only
d) I, II, and III only
c) II and III only
a) II and III only
b) I and II only
c) I, II, and III only
d) I and III only
c) I, II, and III only
a) 2 mol
b) 5 mol
c) 6 mol
d) 3 mol
c) 6 mol
