Exam 1
ionization energy
- Energy required to removes an electron from an atom in the gas phase
Aufbau Principle
-Finding the electron configuration from building up from H and putting electrons into orbitals -Generally as the ℓ quantum number increases the energy is slightly higher -Exceptions to the Aufbau Principle -occurs where the subshell can be completely filled or half filled
Hund's Rule
-electrons should be placed into separate orbitals before going into the same orbital -Substances with unpaired electrons are called "paramagnetic" as they are attracted towards a magnetic field -Substances will all paired electrons are "diamagnetic" as they are repelled from a magnetic field.
Rutherford
-overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny, heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure
Write the ground-state electron configuration of a europium atom
. [Xe] 4f^7 6s^2
What is the energy, in Joules, of a photon of wavelength 150 nm?
1.33 x 10^-18 J
An alpha particle (mass = 6.644 x 10-27 kg) is ejected from a nuclear detonation at a velocity of 5 x 10-7 m/s with an uncertainty of 500 km/s. What is the minimum uncertainty in the position of the alpha particle?
1.59 x 10^-14 m
Consider a potato of mass 300 g that has just been fired from a potato gun and is flying at 12 km/s. What is the potato's de Broglie wavelength (λ)? Your answer must be expressed in meters. Only enter numbers, no units.
1.84 x 10^-37 m
In an atom, what would be the maximum number of electrons having the quantum numbers n = 6 and ℓ = 2
10
What is the ground state electron configuration for chromium
1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5
What is the correct ground state electronic configuration of magnesium, Mg
1s^2 2s^2 2p^6 3s^2
What is the ground state electronic configuration of selenium (Se)?
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^4
What is the subshell notation and the number of orbitals that can have the quantum numbers n = 2, ℓ= 1?
2p ; 3
The work function for lithium is 279.7 kJ/mol (meaning kilojoules per mole of electrons). If UV light of wavelength 240 nm is shone on the surface of Li, what is the kinetic energy of an ejected electron in joules?
3.6 x 10^-19 J
How many electrons could be described by the quantum numbers n = 2 and ms = +1/2?
4
Light with a frequency of 7.18 x 10^14 Hz lies in the violet region of the visible spectrum. What is the wavelength of this frequency of light? Answer in units of nm but do not include the units in your answer
418.0000
Use the Rydberg formula for atomic hydrogen to calculate the wavelength for the transition from n = 4 to n = 2.
486 nm
The three quantum numbers for an electron in a hydrogen atom in a particular state are n = 4, \ellℓ= 1, m\ellℓ=1. The electron is located in what type of orbital?
4p
Which statements agree with Dalton's Theory of the Atom? Please check all that apply.
Atoms combine in whole-number ratios Atoms of the same element have the same masses. Atoms are indestructible ("uncuttable").
other trends
Easier the bigger you are (up to down) Harder the smaller it gets (left to right) Hardest one to pry is helium Easiest is cesium Fluorine wants the electrons more than any other electron
Which of the following statements is true regarding electromagnetic radiation?
Electromagnetic radiation with a wavelength of 600 nm has a frequency that is lower than that with a wavelength of 400 nm.
Which of the following statements concerning the Schrödinger equation and its solutions is true? I) Its solutions are wave functions. II) It can be used to determine an electron's exact position.
I
Which of the following statement(s) is/are true about the photoelectric effect? I) The sum of the work function and kinetic energy of an ejected electron is proportional to the frequency of incident light. II) Given light of high enough intensity, electrons can be ejected from any surface. III) Einstein employed the concept that photons have quantized amounts of energy to explain the effect.
I & III
Which of the following statements concerning the Schr¨odinger equation and its solutions is true? I) Its solutions are wave functions. II) It can be used to determine an electron's exact position. III) Both attractive and repulsive V (r) terms are used when solving the Schr¨odinger equation for the hydrogen atom
I only
Which of the following sets of quantum numbers are valid, i.e. don't violate any boundary conditions? I) n = 3, \ellℓ= 2, m\ellℓ = -2, ms = +1/2 II) n = 9, \ellℓ= 5, m\ellℓ = 6, ms = +1/2 III) n = 2, \ellℓ= 1, m\ellℓ = 0, ms = +1 IV) n = 2, \ellℓ= 0, m\ellℓ = 0, ms = +1/2
I, IV
Particle in a box
No potential Energy - Must start and end at 0 at wall - Must be continuous function 1st solution y= sin(xpi/L) L=10 One hump is the most basic solution n=1 2nd solution n=2 *whatever put in for x is the number of humps Walls are not nodes Node= must cross axis n-1 Nodal regions define the shape Wave function- probability ... square nodal of finding particle in that region Higher energy, higher frequency, more humps
Pauli Exclusion Principle
No two electrons can have the same set of quantum numbers. This means that each orbital ( n,ℓ,mℓ ) can have only two electrons in it. One with each value of the spin ( ms ).
The work function of a silver surface is 4.73 eV. Two photons of 2.5 eV each hit the silver. What happens?
Nothing. The photons just bounce off the surface.
Which elements are correctly listed in order of INCREASING ionization energy
O < F < Ne
Who observed floating oil drops?
Robert Millikan
A neutral atom has a ground state electronic configuration designated 1s^2 2s^2 2p^2. Which of the following statements concerning this atom is/are true?
The atom has electrons in four orbitals. The atom has two unpaired electrons. The atom contains 6 protons. The atom has 2 core electrons and 4 valence electrons.
The Schrödinger equation yields an infinite number of solutions for the possible location of an electron in a hydrogen atom. Each of these solutions has a(n) ______ and a(n) _____ . The solutions from the Schrödinger equation are labeled by ________.
wave function energy quantum number
Electromagnetic radiation - relationship between E, ν, and λ
λ = c / ν E = h × ν
What is the correct order of increasing energy?
microwaves, visible light, ultraviolet light, x-rays, γ-rays
The size of an atomic orbital is determined by which quantum number
n
Which set of quantum numbers does NOT provide a satisfactory solution to the wave equation
n = 2, ℓ = 0, mℓ = −1
An electron in a 3d orbital could have which of the following quantum numbers?
n = 3 ; l= 2 ; ml= 0
An electron in a hydrogen atom could undergo any of the transitions listed below, by emitting light. Which transition would give light of the shortest wavelength?
n = 4 to n = 1
Which of the following electronic transitions for a hydrogen atom would correspond to the highest energy emission found in the Balmer series?
n = 4 to n = 2
Rank the following species from least to greatest electron affinity: F, Ge, S, As, Se
As < Ge < Se < S < F
Arrange the following atoms in order of increasing radius: Li, Au, C, Cs.
C < Li < Au < Cs
An excited electron in a hydrogen atom could undergo any of the transitions listed below, by emitting light. Which transition would emit light of the longest wavelength?
n = 5 to n = 4
The work function for calcium, Ca, is 2.90 eV. When I shine light of a certain wavelength and intensity on the calcium surface, electrons are ejected What would happen if I changed the light shining on the calcium surface to have the same intensity but a shorter wavelength?
Electrons would still be ejected, but they would have a higher kinetic energy.
Fm
Fermium
F
Fluorine
Fr
Francium
Fe
Iron
La
Lanthanum
Lr
Lawrencium
Li
Lithium
Lu
Lutetium
In the 20th century, quantum mechanics addressed the failures of classical mechanics by introducing the concept of wave-particle duality. Why did classical mechanics able to explain the world just fine up until then?
Macroscopic objects can be modeled purely as particles because their wavelength is so small compared to their scale that it can be neglected for most purposes and still give a good description of their behavior.
Effective nuclear charge
amount of charge outer most shell feels What positive amount from the nucleus that the outermost electron "feels"
Which set of compounds best illustrated the law of multiple proportions?
SO2, SO, SO3 The Law of Multiple Proportions says that an element can sometimes combine with another element in varying ratios. So in each compound here the number of sulfur atoms stays the same, but the number of oxygen atoms varies.
uncertainty principle
The position and momentum of a particle cannot be simultaneously measured with arbitrarily high precisio
We conduct an experiment by shining 500 nm light on potassium metal. This causes electrons to be emitted from the surface via the photoelectric effect. Now we change our source light to 450 nm at the same intensity level. Which of the following is the result from the 450 nm light source compared to the 500 nm source?
The same number of electrons would be emitted, but they would have a higher velocity
Trends Left to Right
They are both related to the fact that as you move from left to right the effective nuclear charge, Zeff, is increasing. This means the valence electrons feel a stronger attraction to the nucleus. This leads to a smaller radius and a higher ionization energy
Trends Top to Bottom
They are both related to the fact that as you move from top to bottom, the effective nuclear charge, Zeff, is essentially constant, but the valence electrons are in higher and higher n shells.
As one obtains the emission spectrum of an atom, electrons must be moving from higher to lower energy levels within an atom
True
Failure of classical physics - photoelectric effect: theory and application
When light shines on the surface of a metallic substance, electrons in the metal absorb the energy of the light and they can escape from the metal's surface. This is called the photoelectric effect, and it is used to produce the electric current that runs many solar-powered devices. Using the idea that light is a wave with the energy distributed evenly throughout the wave, classical physicists expected that when using very dim light, it would take some time for enough light energy to build up to eject an electron from a metallic surface. WRONG!! Experiments show that if light of a certain frequency can eject electrons from a metal, it makes no difference how dim the light is. There is never a time delay A classical model for the photoelectric effect could not be verified experimentally - it predicts that there is no relationship between the intensity of the incident light and the energy of the expelled electrons
The following three statements refer to the Bohr theory of the atom. Z1) An electron can remain in a particular orbit as long as it continually absorbs radiation of a definite frequency. Z2) The lowest energy orbits are those closest to the nucleus. Z3) An electron can jump from an inner orbit to an outer orbit by emitting radiation of a definite frequency. Which response contains all the statements that are consistent with the Bohr theory of the atom and no others?
Z2 only
What is the electronic configuration of Sn^4+
[Kr]4d^10
What is the ground-state electron configuration expected for iodine?
[Kr]5s^2 4d^10 5p^5
The shape of a d orbital is thought to resemble...
a cloverleaf.
The quantum mechanical approach to atomic structure permits the calculation of...
a region about the nucleus in which an electron of specified energy will probably be found.
Rutherford's Gold Foil Experiment
better understanding of atomic structure. an atom has a small, dense, positive nucleus
Louis de Broglie proposed that ________ can be described in terms of wavelength and energy, a property called wave-particle duality. The equation he developed to describe the wavelength of matter predicts that ______ the smaller its wavelength must be and ______ the larger its wavelength must be.
both electromagnetic radiation and matter the more massive an object the slower the velocity
The transition metals are elements with partially filled...
d subshells
Thompson
discovered electrons
Einstein
e=MC^2
One consequence of wave-particle duality is the uncertainty principle that at any one moment, you can know _____ the location _____ the trajectory of an object.
either, or
J.J. Thomson observed properties and behaviors of______ using ________
electrons a cathode ray tube
J.J. Thomson's Cathode Ray Tube Experiment
electrons are extremely small, sub atomic negative particles
Bohr model theory
energy is quantized between the atom
During Rutherford's gold foil experiment, the majority of the positively charged alpha particles deflected off of the gold nuclei.
false Because the nucleus of an atom is very small, the majority of the alpha particles passed right through the gold foil without encountering a nucleus that would cause deflection.
Fill in the blanks: potassium is one of the most well-known elements in the alkali metal ______. It is in the_______ which makes it a ______ element. Its single valence electron is in the ______ subshell of the ______ shell, making it very reactive. It reacts readily with non-metals to form _______ .
family; s block; main group; ℓ = 0; n = 4; salts
Arrange the following types of photons of electromagnetic radiation in order of decreasing energy: red light, radio, x-rays, gamma rays, infrared.
gamma rays > x-rays > red light > infrared > radio
One of the boundary conditions for Particle in a Box is that the box's walls have _______ potential energy, and a result the particle has ______ probability of being found at the walls.
infinite zero
In the context of quantum mechanics, the radial distribution function...
is a plot of the probablility of finding the electron some distance from the nucleus.
Electron Affinity
is the energy released from an atom upon the addition of an electron to form the anion -electron affinity has essentially no periodic trend -Electron affinity- how much energy is released when one electron is added to a species
Compared to a 280 nm photon, a 320 nm photon has:
longer wavelength, lower frequency, lower energy
The orientation in space of the orbital of the electron is described by which quantum number?
m fancy l
Which element is located in the family represented by the valence configuration: ns^2 np^3 ?
nitrogen
What is the notation for the valence-shell configuration of "coinage" metals (Cu, Ag, Au)? Include the outermost d-electrons.
ns^1 (n - 1)d^10
Wavefunctions are a representation for...
orbitals
The Group IIIA elements (sometimes noted Group 13) through the Group VIIIA (sometimes noted Group 18) elements form an area of the periodic table where the electron sublevels being filled are...
p orbitals
An orbital has a principal quantum number of 4. The magnetic quantum is -1. What is the shape of the orbital?
p, d or f
Consider the solution to the Schrodinger equation involving a single particle in a one-dimensional box. If all other variables were unchanged, decreasing the length (L) of the box from 400 nm to 200 nm would ______ the energy (E) of the particle. If all other variables were the same, a particle of mass 3 x 10-24 kg would have ______ energy as a particle of mass 6 x 10-24 kg. As the principal quantum number (n) is increased, the energy (E) of a particle would _______
quadrupled twice as much increase exponentially
Elements with valence electrons in the second energy level are all in the...
second period
Paired Electrons in the same atom will differ because of their...
spin.
In the 18th century, Proust found that no matter how one formed the compound copper carbonate CuCO3 the ratio of copper to carbon to oxygen always remained the same. In this way, Proust established experimental evidence to support
the Law of Definite Proportions.
Failure of classical mechanics—emission spectra
the continuous spectrum or pattern of bright lines or bands seen when the electromagnetic radiation emitted by a substance is passed into a spectrometer. The spectrum is characteristic of the emitting substance and the type of excitation to which it is subjected.
Bohr's theory of the hydrogen atom assumed that...
the electron can exist in any one of a set of discrete states (energy levels) and can move from one to another by emitting or absorbing radiation.
100 grams of calcium carbonate (CaCO3) decomposes upon heating into 56 grams of calcium oxide (CaO) and 44 grams of carbon dioxide (CO2). This experiment is an example of
the law of conservation of mass
Hydrogen peroxide decomposes into water and oxygen when exposed to heat or light. A tightly capped bottle of hydrogen peroxide is placed on a balance and exposed to light for three weeks. The mass reading on the balance does not change across these three weeks. This experiment is an example of
the law of conservation of mass
Millikan's Oil Drop Experiment
the magnitude of the charge of an electron is 1.6X10^-19C
Which of the following experiments provided evidence that the electrons in atoms are arranged in distinct energy levels?
the observation of line spectra from gas discharge tubes
Different elements have different series of photons that are absorbed or emitted because...
the orbital energy levels differ for different elements.
The photoelectric effect provided strong evidence for...
the particle nature of light.
In the late 19th century, classical physics failed to accurately predict the behavior of black-body radiators in an event that was named _______ . Fortunately, Max Planck solved this problem by proposing that electromagnetic radiation carried energy ________
the ultraviolet catastrophe in discrete packets