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CHEM 219 Exam #2 (Questions With A+ Solutions)
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CHEM 219 Exam #2 (Questions With A+ Solutions)
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CHEM 219 Exam #2 (Questions With A+ Solutions)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? Right Ans - 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? Right Ans - 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
Right Ans - 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?
Right Ans - 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 Right Ans - Gamma waves
Energy of a photon is ______ proportional to frequency, and _______ proportional
to wavelength Right Ans - directly, inversely
What is observed when a noble gas is heated and the emitted light shone
through a prism? Right Ans - 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 Right Ans - model of the atom in which electrons move rapidly
around the nucleus in paths called orbits
Electromagnetic Energy Right Ans - a form of energy that travels through
space in the form of waves
Quantum Theory Right Ans - describes mathematically the wave properties
of electrons and other very small particles
Periodic Properties Right Ans - 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? Right Ans - Ionization energy is the
amount of energy required to remove an electron from a neutral, gaseous
atom
atomic radius trend Right Ans - 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 Right Ans - 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? Right Ans - 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.
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