Ch. 8 Online Notes Physical Science
What is the energy of a photon of light with a frequency of 5.4 x 1015 Hz? (h = 6.63 x 10-34 J⋅s)
3.6 x 10-18 J
An unknown element has two primary isotopes, one with a relative abundance of 25.34% and a mass of 52.35 u, and another with a relative abundance of 74.66% and a mass of 54.87 u. What is the atomic weight of this element?
54.23 u (0.2534 x 52.35 u) + (0.7466 x 54.87 u) = 54.23 u
Calculate the wavelength of the red line (n = 3) in the hydrogen line spectra according to Balmer's equation. 1λ = R(122 - 1n2) where R = 1.097 x 107 1/m
6.6 x 10-7 m
The principal quantum number is given the symbol _____and has positive, whole-number values starting with______.
<s v="1"><p><t s="9">n</t></p></s> 1
Which element has the electron configuration 1s22s22p63s23p1?
AI
Which of the following statements correctly describe Dalton's atomic theory?
All matter consists of atoms. Compounds result from the specific combination of a specific ratio of atoms of different elements. Atoms of the same element are identical.
Electrons can only exist in certain orbits.
Allowed orbits
Which of the following statements correctly describe electronic transitions in an atom?
An electron absorbs energy to move to a higher-energy orbit. The energy absorbed or emitted in an electronic transition is exactly equal to the energy difference between the two orbits.
Which of the following statements correctly describe the Bohr model?
An electron can only exist in fixed orbits around the nucleus. An electron in an allowed orbit does not emit radiant energy as long as it remains in the orbit.
Which of the following statements correctly describes the Pauli exclusion principle?
An orbital can hold a maximum of two electrons as long as they have opposite spins.
Which of the following statements correctly describe an orbital?
An orbital defines the probability of finding an electron in a given region of an atom. Orbitals have characteristic shapes and sizes.
What two pieces of information must be known to calculate the atomic weight of a particular element?
Atomic mass of each isotope Relative abundance of each isotope
Which of the following statements correctly defines atomic weight?
Atomic weight is the weighted average, relative to carbon-12, of all naturally occurring isotopes for a given element.
Dalton's atomic theory stated that matter consists of tiny indivisible particles called ____________, which combine in definite whole-number ratios to form ____________.
Atoms Compounds
Which of the following statements about line spectra of atoms (pictured) in the gas phase is true?
Atoms in the gas phase only emit radiation at certain frequencies. Each atom has a characteristic line spectrum. Each line in a line spectrum represents a specific energy.
The four lines that make up the visible region of the line spectra of hydrogen became known as the ________ series.
Balmer
model of an atom that shows electrons in circular orbits around the nucleus
Bohr Model
Which of the following statements correctly describe cathode rays?
Cathode rays are identical no matter what their source. A cathode ray consists of negatively charged particles. The discovery of cathode rays showed that an atom can be broken down into smaller particles.
Which of the following statements about the evolution of the atomic concept are true?
Democritus stated that matter is composed of small indivisible particles called atoms. Some Greek philosophers theorized that matter is continuous.
Which of the following equations correctly reflects the relationship between energy and frequency?
E = hf
Energy of the innermost orbit
E1
Energy of the orbit farthest from the nucleus
EH
Energy of the orbit closest to the nucleus
EL
Which of the following are true about the rules of writing the electron configuration of an atom?
Each orbital contains a maximum of two electrons. The sum of the electrons in all orbitals is equal to the atomic number.
Which of the following statements can be attributed to the quantum mechanical model of the atom?
Electrons occupy a three-dimensional space near the nucleus. The wave nature of the electron is emphasized.
Energy of a particular orbit
En
Which of the following properties are described by the angular momentum, principal, spin, and magnetic quantum numbers?
Energy Orientation in space Direction of spin
What does it mean for energy to be quantized?
Energy is absorbed or emitted in discrete units.
Which statement correctly describes what occurs when the electron of the hydrogen atom moves from the n = 1 to the n = 3 energy level?
Energy with a frequency of 2.92 x 1015 Hz is absorbed by the atom.
Which of the following statements correctly describes isotopes?
Isotopes have different numbers of neutrons.
Select all the statements that accurately characterize the quantum mechanics theory of the atom.
It considers the wave nature of electrons. It states where electrons might be found, rather than where they definitely are.
Which of the following is a consequence of the Heisenberg uncertainty principle?
It is not possible to assign an electron to a fixed orbit.
Which of the following statements correctly describe wave-particle duality?
Large objects have wavelengths that are too small to be detected or measured. All matter exhibits wavelike motion.
A particular isotope of an element is represented by the symbol 815O. Match the correct term with the correct number.
Mass Number: 15 Number of Protons: 8 Number of Neutrons: 7
Which of the following statements correctly describe the properties of a photon?
Matter cannot absorb or emit a fraction of a photon. Photons are discrete units of light energy.
The determination of the charge on a single electron
Millikan's Oil Drop Experiment
Which of the following options correctly describe the results of the experiments performed by Thomson and Millikan?
Millikan's experiments allowed him to calculate the charge and mass of the electron. Thomson studied the behavior of cathode rays. Millikan measured the electrical charges of oil droplets.
Rutherford's gold foil experiment was very important in developing the nuclear model of the atom. Which of the following statements correctly describe the observations made and the implications of each for atomic structure?
Most alpha particles passed straight through the foil, implying that the atom consists largely of empty space. A few alpha particles showed major deflections, and some were reflected, indicating the presence of a dense, positive core.
Which of the following options correctly describe the problems with the solar system model of the atom?
Orbiting electrons would emit light. Orbiting electrons would accelerate. Orbiting electrons would accelerate.
Which of the following options correctly describe Rutherford's experiment to discover the nature of the atom?
Particles were detected by a screen that produced small flashes of light when struck. Measurements of the angles between the screen, metal foil, and the source determined the scatter pattern of the particles.
An orbital defines the _________ of finding an electron in space.
Probability
jumps of electrons from one orbit or energy state to another
Quantum leaps
the discovery of the nucleus of the atom
Rutherford's metal foil experiment
Which of the following options correctly describes the limitations of the Bohr model of the atom?
The Bohr model cannot account for the behavior of multielectron species.
What does the Bohr equation allow one to calculate?
The allowed energies of the electron in a hydrogen atom
Which of the following statements about the angular momentum quantum number is true?
The angular momentum quantum number defines energy sublevels with specific shapes. The angular momentum quantum number describes energy sublevels that are associated with each principal quantum number.
Which of the following statements correctly describe the atomic number of an element?
The atomic number is equal to the number of protons in the nucleus. Each element has its own unique atomic number.
A particular isotope of an element is represented by the symbol 3579Br. Which of the following options correctly interpret this symbol?
The element contains 35 protons in the nucleus. The element contains 44 neutrons in the nucleus.
What is an electron volt?
The energy of an electron moving through a potential of 1 V
What does the equation developed based on the Bohr model of the atom allow one to calculate?
The energy that is emitted or absorbed when the hydrogen electron moves between energy states
Which of the following defines the ground state of an atom?
The lowest energy state
Which of the following statements correctly describe the mass number of an element?
The mass number is often written as a left superscript next to the chemical symbol. The mass number is given by the sum of the protons and neutrons in the nucleus.
Which of the following statements correctly describe subatomic particles?
The mass of an electron is negligible compared to the mass of a proton. The electrons are located outside the nucleus of an atom.
Which of the following statements correctly describe the principal quantum number n?
The n describes the distance of the electron from the nucleus. The n can have any positive whole-number value.
Which of the following correctly describe the current model of the atom?
The nucleus is a very small fraction of the total volume of the atom. The number of protons equals the number of electrons in a neutral atom. The mass of the atom is mostly the mass of the neutrons and protons.
Which of the following pieces of information are important when writing the electron configuration of an element?
The number of electrons in the atom The energy ordering of the orbitals The number of orbital orientations
What information is contained in the atomic number of an electrically neutral element?
The number of protons The number of electrons
Which of the following statements correctly describe the spin quantum number?
The spin quantum number is a property of the electron itself. The spin quantum number has two possible values.
Which of the following options interpret the electron configuration 1s22s22p3 correctly?
There are 2 electrons in the 1s sublevel. The 2 electrons in the 2s sublevel have opposite spin.
Which of the following statements correctly describe the observations that led to the development of the nuclear model of the atom?
Thomson measured the charge-to-mass ratio for an electron. Rutherford determined that the mass of an atom is concentrated in the central region.
Which of the following statements about Thomson's model of the atom is true?
Thomson postulated that electrons are embedded in a massless blob of positive charge.
The discovery of the electron
Thomson's experiment with cathode rays.
True or false: Line spectra of atoms in the gas phase do not show a continuous spread of frequencies.
True
Which of the following is an electron pair?
Two electrons with opposite spin directions in the same orbital.
When is the potential energy of an electron considered to be zero?
When the electron is removed from the atom
An electron moves to a higher-energy orbit by ______ energy from high temperatures or electrical discharges and moves to a lower-energy orbit by ______ energy in the form of light. The energy absorbed or emitted must exactly equal the energy ______ between the two orbits.
absorbing; emitting; difference
energy sublevel, shape of the orbital
angular momentum quantum number
Isotopes are atoms of the same element that have the same ______ number but a different ______ number. This is because isotopes have the same number of protons but a different number of ______.
atomic; mass; neutrons
All atomic masses are determined relative to a(n) _____-12 standard; this isotope is defined to be exactly 12 u.
carbon
The electron ____________of an element shows the distribution of electrons within the orbitals of the atom.
configuration
According to the equation, E = hf, the energy of a photon is ______ proportional to the frequency of radiation, where h is a proportionality constant known as ______ constant and f is the frequency of radiation.
directly; Planck's
Thomson's experiments with cathode rays determined that atoms contained even smaller particles called ______, which have a ______ charge.
electrons; negative
The angular momentum quantum number describes _____. Each of these is identified with a _____.
energy sublevels; letter
The number of possible sublevels for each main energy level is _______ the principal quantum number.
equal to
The Pauli ________ principle states that no two electrons in the same atom can have the same four quantum numbers. This means that the maximum number of electrons accommodated by any orbital is _________.
exclusion two
The quantum mechanics model describes the location of electrons as ______.
fuzzy statistical representations
An electron in the _____ state will jump to a(n) _____ state when it absorbs a quantum that is equal to the difference in energy between the two states.
ground; excited
orientation in space
magnetic quantum number
The ______ number of an atom is the sum of its protons and ______.
mass; neutrons
In Rutherford's gold-foil experiment, he observed that most of the alpha particles passed straight through the foil, indicating that the atom is ______. Some alpha particles were deflected at large angles, and others were reflected back toward the source, which caused him to conclude that the atom contains a dense, ______ charged nucleus surrounded by electrons.
mostly empty space; positively
Quantum number for an orbit
n
Thomson discovered that cathode rays emanate from the ____ electrode. This among other experimental evidence caused him to postulate that they consist of particles of the same charge. However, the major breakthrough made by Thomson was that the charge-to-mass ratio of the particles that make up cathode rays are _____ for each source.
negative the same
When an electron is in the orbit closest to the nucleus, its value for potential energy will be _____. When an electron is completely removed from the nucleus, its potential energy is _____.
negative; zero
In the solar system model of the atom, the __________ is the Sun and the _________are the planets. The _________attractions between these species act as the gravitational attraction.
nucleus electrons electrical
An atom is composed of a very dense central ________ containing ___________, which are positively charged, and neutrons, which have __________ electric charge.
nucleus protons no
The magnetic quantum number indicates the ______ of an orbital in space.
orientation
Albert Einstein stated that light follows the quantum concept proposed by Planck and consists of discrete units of energy called _________.
photons
The Heisenberg uncertainty principle states that it is not possible to know the exact momentum and________of an electron simultaneously. In terms of atomic structure, this means that we cannot determine fixed orbits for electrons but can only determine the __________ of finding an electron in a given region of space.
position probability
Since it was known that the atom was electrically neutral, Thomson proposed that the atom was a massless blob of _____ charge with _____ charged particles embedded in it like "raisins in plum pudding."
positive negative
main energy level of electron
principal quantum number
The atomic number of each element is unique and represents the number of ______ in the nucleus. Since an atom is neutral, this number is also equal to the number of ______ present.
protons and electrons
Energy is not continuous but is quantized or divided into "packets," each of which contains a definite amount of energy. Energy "packets" are called _____, and the energy of each "packet" is directly proportional to its _____.
quanta; frequency
Electrons occupy a three-dimensional space near the nucleus.
quantum mechanical model
Electrons do not emit light in their allowed orbits.
radiationless orbits
direction of spin
spin quantum number
An electron not only moves around the nucleus but also _________on its own axis. There are two possible orientations for this behavior, and these are described by the ________quantum number.
spins spin
The electron configuration of an element describes _____.
the distribution of electrons within the orbitals of the atom
Balmer developed an equation based on the _____ line spectrum of the element _____. His equation allowed him to directly calculate the _____ of each line in the line spectrum.
visible; hydrogen; wavelength
All matter behaves as though it moves as a _____. The motion of any particle can be described by the de Broglie equation, which relates wavelength of a particle to its _____ and speed.
wave; mass
Louis de Broglie demonstrated that matter is similar to light in that it has properties characteristic of both _______ and particles. This theory helped to explain the anomalous behavior of ___________in an atom.
waves electrons
