CHEM 219 Exam #2 Exam Questions and Answers Grade
A+
The atomic radii of zirconium (Zr) and hafnium (Hf) are nearly the same despite
the fact that hafnium has 32 more protons and electrons. Which of the following
bests explains this phenomenon? - Answer-Hafnium contains electrons in the 4f
orbitals. These 4f electrons do not effectively shield the higher nuclear charge and
thus Zeff is higher than might be otherwise expected.
Which of the following is true concerning successive ionizations of an atom and its
ions? - Answer-Each successive ionization requires increasing amounts of energy
The energy of a photon equals its Planck's constant (h) multiplied by the speed of
light(c) and then divided by the wavelength. E = hc/λ. If microwaves are changed
to x-rays, what effect does this have on the energy of the photon - Answer-The
energy of the photon increases
Photons are shone on a piece of metal and one electron is ejected for each
absorbed photon. What happens when the wavelength of light is decreased? -
Answer-The ejected electrons would have greater kinetic energy
What type of light on the electromagnetic spectrum has the highest energy per
photon?
X-ray
visible light
microwaves
Gamma waves - Answer-Gamma waves
Energy of a photon is ______ proportional to frequency, and _______
proportional to wavelength - Answer-directly, inversely
What is observed when a noble gas is heated and the emitted light shone through
a prism? - Answer-individual lines of varying colors
, Heating a noble gas promotes its electrons to excited energy states, which then
relax to emit discrete wavelengths of light. When shone through a prism, this
results in individual lines of varying colors.
Bohr Model - Answer-model of the atom in which electrons move rapidly around
the nucleus in paths called orbits
Electromagnetic Energy - Answer-a form of energy that travels through space in
the form of waves
Quantum Theory - Answer-describes mathematically the wave properties of
electrons and other very small particles
Periodic Properties - Answer-properties whose values can be predicted based on
the element's position on the periodic table
Which periodic trend quantifies the amount of energy required to remove an
electron from a neutral, gaseous atom? - Answer-Ionization energy is the amount
of energy required to remove an electron from a neutral, gaseous atom
atomic radius trend - Answer-The atomic radius increases as you move down the
periodic table and to the left. Tantalum is the furthest to the right of this list and
nearer the top and it would be expected to have the smallest atomic radius
ionization energies - Answer-amount of energy a gaseous atom or ion must absorb
to lose its outermost electron.
In general, first ionization energy decreases down a group and increases across a
period
The first five ionization energies of an element are as follows (in kJ/mol): 577.9,
1820, 2750, 11600, 14800. Which of the following elements is most likely to have
these ionization energy values? - Answer-D) Al
there is a large increase in ionization energies from the third to the fourth
ionization. This suggests it is relatively easy to remove three electrons.
A+
The atomic radii of zirconium (Zr) and hafnium (Hf) are nearly the same despite
the fact that hafnium has 32 more protons and electrons. Which of the following
bests explains this phenomenon? - Answer-Hafnium contains electrons in the 4f
orbitals. These 4f electrons do not effectively shield the higher nuclear charge and
thus Zeff is higher than might be otherwise expected.
Which of the following is true concerning successive ionizations of an atom and its
ions? - Answer-Each successive ionization requires increasing amounts of energy
The energy of a photon equals its Planck's constant (h) multiplied by the speed of
light(c) and then divided by the wavelength. E = hc/λ. If microwaves are changed
to x-rays, what effect does this have on the energy of the photon - Answer-The
energy of the photon increases
Photons are shone on a piece of metal and one electron is ejected for each
absorbed photon. What happens when the wavelength of light is decreased? -
Answer-The ejected electrons would have greater kinetic energy
What type of light on the electromagnetic spectrum has the highest energy per
photon?
X-ray
visible light
microwaves
Gamma waves - Answer-Gamma waves
Energy of a photon is ______ proportional to frequency, and _______
proportional to wavelength - Answer-directly, inversely
What is observed when a noble gas is heated and the emitted light shone through
a prism? - Answer-individual lines of varying colors
, Heating a noble gas promotes its electrons to excited energy states, which then
relax to emit discrete wavelengths of light. When shone through a prism, this
results in individual lines of varying colors.
Bohr Model - Answer-model of the atom in which electrons move rapidly around
the nucleus in paths called orbits
Electromagnetic Energy - Answer-a form of energy that travels through space in
the form of waves
Quantum Theory - Answer-describes mathematically the wave properties of
electrons and other very small particles
Periodic Properties - Answer-properties whose values can be predicted based on
the element's position on the periodic table
Which periodic trend quantifies the amount of energy required to remove an
electron from a neutral, gaseous atom? - Answer-Ionization energy is the amount
of energy required to remove an electron from a neutral, gaseous atom
atomic radius trend - Answer-The atomic radius increases as you move down the
periodic table and to the left. Tantalum is the furthest to the right of this list and
nearer the top and it would be expected to have the smallest atomic radius
ionization energies - Answer-amount of energy a gaseous atom or ion must absorb
to lose its outermost electron.
In general, first ionization energy decreases down a group and increases across a
period
The first five ionization energies of an element are as follows (in kJ/mol): 577.9,
1820, 2750, 11600, 14800. Which of the following elements is most likely to have
these ionization energy values? - Answer-D) Al
there is a large increase in ionization energies from the third to the fourth
ionization. This suggests it is relatively easy to remove three electrons.
