CHEM chapter 7 quantum theory and the electronic structure of atoms

What is the Aufbau principle?

as protons are added to the nucleus across the periodic table, electrons are also added to orbitals

the distributions of electrons among orbitals in a many-electron atom is known as its electron ____________

configuration

an orbital with l=2 is called a(n) _ orbital. these orbitals always occur in groups of ________ orbitals of equal energy.

d; five

If a solid object is heated to a high enough temperature it will begin to glow. The color of light it emits depends on the temperature. This relationship between color temperature implies a relationship between _____.

energy and frequency

what is a consequence of the Heisenberg uncertainty principle?

it is not possible to assign well-defined paths for electrons

Bohr postulated that the electron in a hydrogen atom ________

occupies only certain fixed energy levels

electrons, like all other matter, exhibit the dual behavior of both ____________ and waves. since electrons travel like waves their energy is restricted to certain energy _________, each of which is associated with a specific wavelength

particles; levels

electromagnetic radiation consists of particles called __________, each of which has a discrete amount, or quantum, of energy. However, since electromagnetic radiation also has wave properties, each particle is also characterized by a specific _______ and frequency.

photons; wavelength

wavelength

the distance between two identical points on successive waves

what does the equation ΔE=RH(1/n2i−1/n2f) allow one to calculate?

the energy of a photon that is emitted or absorbed when the hydrogen electron moves between energy states

why does each element have its own unique atomic line spectrum?

the lines in the spectrum correspond to the differences between the specific energy states in the atom

frequency

the number of waves that pass a particular point in 1 second

amplitude

the vertical distance from the midline of a wave to the peak or trough

elements in the same group of the periodic table have similar chemical properties because __________.

they have the same valence electron configuration

a given photon of electromagnetic radiation has a characteristic frequency, and thus contains a fixed amount of _________.

energy

which of the following statements correctly describe the de Broglie wavelength for a particle? -the greater the speed of the particle, the greater its wavelength -a fast-moving particle will have a short wavelength -the larger the mass of the particle, the smaller its wavelength -wave behavior is most obvious for small, fast moving particles

-a fast-moving particle will have a short wavelength -the larger the mass of the particle, the smaller its wavelength -wave behavior is most obvious for small, fast moving particles

which of the following electron configurations are associated with increased stability? -a full valence shell or level -a filled sublevel -a half-filled sublevel -any sublevel with only one unpaired electron -a p or d sublevel containing only one electron

-a full valence shell or level -a filled sublevel -a half-filled sublevel

which of the following statements correctly describe gas-phase emission spectra? -a given element may produce more than one line spectrum, depending on experimental conditions -elements in the same group of the periodic table will produce the same line spectrum -a known line spectrum can be used to identify the element that produced it -each element has a unique line spectrum

-a known line spectrum can be used to identify the element that produced it -each element has a unique line spectrum

which of the following statements correctly describe wave-particle duality? -all matter exhibits wavelike motion -matter and energy are different forms of the same entity -only small particles like electrons exhibit wavelike motion -photons are rare particles that exhibit only wavelike behavior -energy and mass can be interconverted

-all matter exhibits wavelike motion -matter and energy are different forms of the same entity -energy and mass can be interconverted

which of the following statements correctly describe an atomic orbital? -an atomic orbital describes the path of an electron orbiting an atom -an atomic orbital defines the probability of finding an electron in a given region of an atom -an atomic orbital is the square of a Schroedinger wave function -an atomic orbital is a Schroedinger wave function

-an atomic orbital defines the probability of finding an electron in a given region of an atom -an atomic orbital is the square of a Schroedinger wave function

-a species that is slightly repelled by a magnetic field is __________ -a species that is attracted to a magnetic field is _________

-diamagnetic -paramagnetic

which of the following statements correctly describe the atom in terms of quantum mechanics? -electrons exhibit behavior of both particles and waves -electrons have certain allowed energy states associated with fixed orbits around the nucleus -the movement of each electron in the atom cannot be explained by classical physics -each electron occupies a three dimensional space near the nucleus. this space is described by a wave function

-electrons exhibit behavior of both particles and waves -the movement of each electron in the atom cannot be explained by classical physics -each electron occupies a three dimensional space near the nucleus. this space is described by a wave function

which statement about the quantum mechanical model of the atom is not correct? -electrons can only occupy fixed energy levels -the region of electron density corresponds to the square of a wave function -electrons occupy fixed orbits at fixed energy levels -an electron occupies a three-dimensional region of probability density

-electrons occupy fixed orbits at fixed energy levels

which of the following statements correctly describe the spin quantum number of the electron? -has a value of +1/2 or -1/2 -depends on the type of orbital the electron is in -is a property of the electron itself -has values of -1 or +1

-has a value of +1/2 or -1/2 -is a property of the electron itself

which of the following statements correctly describe a photon? -a high-frequency photon has low energy -all photons have the same amount of energy -matter cannot absorb or emit a fraction of a photon -a photon is a particle of electromagnetic radiation

-matter cannot absorb or emit a fraction of a photon -a photon is a particle of electromagnetic radiation

a diamagnetic species has _________ a paramagnetic species has ____________

-no unpaired electrons -one or more unpaired electrons

which of the following statements correctly describe how to place electrons in orbitals of the same sublevel? -a pair of electrons is placed in each orbital until all the orbitals of the sublevel are full -one electron must be placed in each orbital of equal (degenarate) energy before electrons are paired up -all unpaired electrons in a sublevel should have parallel spins -unpaired electrons should alternate in their spins

-one electron must be placed in each orbital of equal (degenarate) energy before electrons are paired up - when electrons occupy a subshell with more than one degenerate orbital, Hund's rule states that the lowest energy level is attained by maximizing the number of electrons with the same electron spin -all unpaired electrons in a sublevel should have parallel spins - this reflects the lowest energy configuration possible

which of the following statements correctly describe the Bohr model of the hydrogen atom? -the atom is in an excited state when the electron is in the orbit closest to the nucleus -only certain energy levels are allowed within the hydrogen atom -each energy state of the hydrogen atom is associated with a fixed circular orbit of the electron around the nucleus -the electron can move to a higher energy level by absorbing a photon with energy equal to that of the new energy state -the atom is in its lowest energy state when the electron is in the orbit closest to the nucleus

-only certain energy levels are allowed within the hydrogen atom -each energy state of the hydrogen atom is associated with a fixed circular orbit of the electron around the nucleus -the atom is in its lowest energy state when the electron is in the orbit closest to the nucleus

match each substance and condition to the description of its emission spectrum -solid heated to a high temperature -gaseous substance in an electrical discharge -line spectrum of discrete wavelengths -spectrum of continuous wavelengths

-solid heated to a high temperature -> spectrum of continuous wavelengths -gaseous substance in an electrical discharge -> line spectrum of discrete wavelengths

which of the following statements correctly describe the magnetic quantum number, symbol ml? -the number of possible ml values equals the value of n for a given level -this value is also known as the spin quantum number -the allowed values of ml range from -l to +l -this value indicates the orientation of an orbital in space around the nucleus

-the allowed values of ml range from -l to +l -this value indicates the orientation of an orbital in space around the nucleus

the work function of a metal is -the energy required for a photon to remove an electron from the metal -the kinetic energy that a photon will transfer to the electrons of the metal -the total energy of a photon that is able to free an electron from the metal -a measure of how tightly the electrons are held in the metal

-the energy required for a photon to remove an electron from the metal -a measure of how tightly the electrons are held in the metal

the electron configuration of an atom indicates -the number of electrons in the atom -whether or not an atom's electrons are in the ground state -the energies of the various atomic orbitals -the distribution of electrons among an atom's orbitals

-the number of electrons in the atom -whether or not an atom's electrons are in the ground state -the distribution of electrons among an atom's orbitals

which of the following statements correctly describe the angular momentum quantum number, l? -the number of possible l values equals the value of n -the allowed values of l are determined by the value of n -this number is related to the orientation of the orbital in space -the value of l dictates the allowed values of ml the values of l can range from -n to +n

-the number of possible l values equals to the value of n -the allowed values of l are determined by the value of n -the value of l dictates the allowed values of ml

which of the following statements correctly describe the limitations of the atomic model that preceded Bohr's hydrogen atom model?

-the old model could not explain why electrons did not spiral into the nucleus of the atom -the old model could not explain observed atomic line spectra -the old model could not explain why electrons did not emit energy continuously

which of the following statements best summarizes the practical meaning of the Schroedinger equation? -the probability of finding an electron at any position in an atom is described by a wave function -the electron in a hydrogen atom can only exist at discrete energy levels -it is impossible to know both the position and momentum of a subatomic particle with certainty -electrons absorb photons in order to reach an excited state

-the probability of finding an electron at any position in an atom is described by a wave function

which of the following statements correctly describe the photoelectric effect? -light of any frequency will cause a current to flow providing enough time is given -the threshold frequency differs for different metals used in the photoelectric effect -current begins to flow immediately when light of the correct frequency shines on the metal plate -light that has a frequency greater than the threshold frequency will not cause a current to flow

-the threshold frequency differs for different metals used in the photoelectric effect -current begins to flow immediately when light of the correct frequency shines on the metal plate

rank the sublevels for a particular principal energy level in order of increasing energy for a multielectron atom (lowest at the top, highest at the bottom) -d -p -f -s

1. s 2. p 3. d 4. f

which of the following correctly expresses energy in terms of planck's constant? *E=Rv *E=hv *E=h/cv *E=hc/λ *E=h/v

E=hv E=hc/λ

Energy is quantized. What does this mean?

There is a basic unit of energy that cannot be subdivided further.

what occurs when the electron in a hydrogen atom moves from a higher-energy state to a lower-energy state?

a photon is emitted whose energy is equivalent to the difference between the two energy states

an atomic orbital is ________

a three-dimensional region where a given electron is likely to be found

In order for electrons to be ejected from the surface of a metal by light, the photon must be ___________ by an electron in the metal. For this to occur, the __________ of the photon must be equal to or greater than the energy needed to remove the electron from its energy state. It is the ____________ of the light that is important, not its intensity.

absorbed; energy; frequency

a gaseous element that is subjected to an electrical discharge will emit ______

electromagnetic radiation only at specific wavelengths

what is meant by the term "shielding" in a many-electron atom?

electrons at lower principal energy levels cause electrons at higher levels to feel less electrostatic attraction for the nucleus

why are electrons restricted to certain, discrete energy levels within an atom?

electrons have wavelike motion and are restricted to certain energy states associated with specific wavelengths

each element has its own atomic line spectrum, consisting of fine lines of individual wavelengths that are characteristic for the element. this occurs because the atom contains specific ________ levels, and an atom can only absorb or emit radiation that corresponds to the energy ___________ between these levels.

energy; difference

a central concept in quantum mechanics is that both matter and _________ are alternate forms of the same entity and therefore both exhibit dual characteristics of particles and ________. this model allows a better understanding of the behavior of tiny particles such as electrons.

energy; waves

the Pauli _________ principle guarantees that no two electrons in the same atom habe the same quantum number description. this means that the maximum number of electrons that can be accommodated by any orbital is _______.

exclusion; 2

the speed of a wave is determined by multiplying the __________ of the wave by its wavelength. in a vacuum, all electromagnetic radiation travels at a constant speed, the speed of _______, which is equal to 3.00 x 10^8 m/s.

frequency; light

An atom is in its lowest energy state, or ____ state, when its electrons are in the lowest possible energy levels. If an electron in the atom absorbs a photon of radiation that is equal in energy to the difference between two energy states it will move to a higher energy state and the atom is said to be in the ______ state.

ground; excited

in the Bohr hydrogen atom, a higher value for the quantum number n indicates that the electron is at a ________ energy level, and is ___________ to the nucleus.

higher; farther from

a beam of light of specific frequency is allowed to shine on a metal diode. which of the following equations correctly relate the energy transferred by the photon to an electron in the metal? hv = KE/W W = hv + KE hv = KE + W hv = KE -W

hv = KE +W

the frequency of a wave is _______ proportional to its wavelength, and ________ to its speed.

inversely; directly

all electromagnetic waves travel at the same speed in a vacuum; this is commonly known as the speed of _______. the radiation has an electric field component and a(n) _________ field component.

light; magnetic

when drawing an orbital diagram; orbitals of _______ energy are filled first. by convention, the ___________ electron in a given orbital is designated as ↑ and the direction of the arrow indicates the electron ________.

lower; first; spin

a moving particle can exhibit wavelike properties. these properties are related to the _______and ________ of the particle.

mass; velocity

the principal quantum number is given the symbol _____ and has positive, whole-number values starting from _.

n; 1

Heisenberg's uncertainty principle states that it's not possible to know the exact momentum and __________ of a particle simultaneously. in terms of atomic structure, this means that we cannot determine well-defined ___________ for electrons but can only determine the ________ of finding an electron in a given region of space

position; positions; probability

a condensed electron configuration includes a noble gas core. the notation begins with the symbol of the noble gas that is ________ to the element being depicted. the noble gas symbol is enclosed in ________.

previous; brackets

an atomic orbital defines the __________ of finding an electron in a particular region of an atom. this electron density is defined by the square of the Schroedinger __________ function.

probability; wave

Energy is not continuous, but is quanitized or divided into "packets" each of which contains a definite amount of energy. An energy "packet" is called a(n) _____ and the energy of each "packet" is directly proportional to its_____.

quantum; frequency

which electron subshell has the greatest penetrating power at any given energy level?

s

the angular momentum quantum number l indicates the ________ of an orbital in an atom. a value of l=0 indicates a(n) ____ type of orbital while a d orbital is indicated by an l value of ________.

shape; s; 2

all waves in the electromagnetic spectrum travel at the same __________ through a vacuum, but differ in their frequency and wavelength. a wave with a long (large) wavelength will have a _________ frequency.

speed; low

An electron not only moves around the nucleus but also _____ on its own axis, thus generating a tiny _____ field. The direction of this field is described by the ______ quantum number m(s), which is not related to any specific orbital but is a property of the electron itself.

spins; magnetic; magnetic

True or false: electromagnetic energy whose frequency is below the threshold frequency for a given metal cannot dislodge electrons, regardless of its intensity.

true (Einstein proposed that electrons were dislodged by absorbing individual photons of light. It is the energy of individual photons, and not their overall intensity, that determines whether electrons will be dislodged)

a p orbital has _________ regions or lobes of high electron probability, on either side of the nucleus. each principal quantum level from n=2 and above has three p orbitals which are identical in size, shape, and energy, but differ in ________.

two; orientation

Planck postulated that energy ____________

was quantized rather than continuous

the Schroedinger wave equation relates the energy of an atom to its electrons in terms of the _______ function of the electron. each solution to the equation represents an allowed _______ state of the atom and is associated with a particular atomic orbital

wave; energy