Chem Ch. 2

Thermal energy

Energy associated with the random motion of atoms and molecules

Which of the following statements correctly reflect the law of conservation of energy? Select all that apply.

Energy can neither be created nor destroyed. Energy can be converted from one form to another.

Electrons and protons

The subatomic particles that bear Coulombic charges

Determine the wavelength (in meters) of radiation with a frequency of 4.60 × 107 s−1.

6.52 m

The positively charged particle in the nucleus of an atom is called a(n) ______. Its charge is equal in magnitude but opposite in sign to that of a(n) ______.

proton; electron

Element

A substance that cannot be broken down into simpler substances

Which of the following correctly expresses energy in terms of Planck's constant? Select all that apply.

E = hc/λ E = hν

A

Mass number: the total number of protons and neutrons in the nucleus

Which of the following options correctly describe the parameters that define waves? Select all that apply.

The wavelength of a wave is the distance between two successive peaks or troughs. The units of frequency are s-1. Frequency is represented by the symbol ν.

Electrostatic energy

Energy resulting from the interaction of charged particles

Kinetic energy

Energy that results from motion

The energy of a photon with a frequency of 1.0 x 1015 s-1 is equal to ______ J.

6.6 x 10-19

Which of the following statements correctly define electromagnetic radiation? Select all that apply.

Electromagnetic radiation exhibits wave behavior. Visible light is a type of electromagnetic radiation.

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

Visible light forms a small part of the __________________ spectrum, which includes other types of radiation. All radiation exhibits ____________________ like behavior.

electromagnetic wave

Which best describes the relative masses of the subatomic particles?

electron < proton ≈ neutron

The _____ number of an atom is equal to the sum of the protons and _____ in the nucleus of the atom.

mass; neutrons

Which statement correctly describes the quantum number n with reference to the Bohr model of the hydrogen atom? Select all that apply.

n indicates the energy level of an electron in the atom. n can have any positive, whole-number value greater than or equal to 1. An electron with n = 2 is at higher energy than an electron with n = 1.

James Maxwell proposed that light consists of waves, and that an electromagnetic wave contains both an electric component and a magnetic component. These two components travel in _____________ planes.

perpendicular

Electromagnetic radiation consists of particles called ____________, which are characterized by a specific wavelength and _______________.

photons; frequency

In a photoelectric cell, an electric current is produced by shining a light on a metal plate. The minimum frequency required to cause a current to flow is called the ______________________ frequency.

threshold

Rutherford's gold foil experiment was very important in developing the nuclear model of the atom. Select all the statements that correctly describe the observations made and the implications of each for atomic structure.

-Most α particles passed straight through the foil, implying that the atom consists largely of empty space. -A few α particles showed major deflections, indicating the presence of a dense central core within the atom.

Arrange the atomic symbols in order of decreasing number of neutrons in the nucleus. (Highest number of neutrons at the top, lowest number of neutrons at the bottom.)

110Pd 111Cd 109Ag

An unknown element has two isotopes: one whose mass is 114.998 amu (25.00% abundance) and the other whose mass is 117.986 amu (75.00% abundance). The average atomic mass of the element is equal to _____.

117.24

Z

Atomic number: the number of protons in the nucleus

Chemical energy

Energy stored in the structure of a compound

The SI unit of energy is the ________, which is abbreviated by the symbol ____________?

Joules J

Which of the following statements correctly describe Rutherford's experiment? Select all that apply.

This experiment used α particles to probe atomic structure. The pathway followed by the α particles was tracked using a fluorescent zinc-sulfide screen. An α particle was known at this time to be positively charged.

Place the following types of electromagnetic radiation in order of increasing wavelength (shortest at the top to longest at the bottom). Instructions

X ray UV Radiation Visible Light IR Radiation Radio Waves

Which of the following correctly reflects the relationship between energy and frequency?

E = hν

750 nm

4.00 × 1014 s-1

600 nm

5.00 × 1014 s-1

450 nm

6.67 × 1014 s-1

Wavelength and frequency are _____ proportional to each other. As wavelength increases, frequency will _____.

inversely; decrease

According to the Bohr model for the hydrogen atom, the energy of the atom is not continuous but has certain discrete energy ___________, each of which is related to a fixed circular_______________ of the electron around the nucleus. The farther the electron is from the nucleus, the _____________ the energy of the system.

levels; orbit; higher

An emission spectrum showing discrete, specific wavelengths is called a _____.

line spectrum

Potential energy

Energy possessed by an object due to its position

True or false: Both heat and work can be measured in joules.

True

In Bohr's model of the atom, the quantum number n is associated with the _____ of an electron orbit. The lower the n value, the _____ the electron is to/from the nucleus and the _____ the energy level.

energy; closer; lower

Which of the following correctly describe atomic structure? Select all that apply.

-The protons and neutrons together comprise most of the mass of the atom. -The number of protons equals the number of electrons in a neutral atom. -The nucleus comprises a very small fraction of the total volume of the atom.

Calculate the energy of a photon of orange light with a wavelength of 600. nm.

3.32 × 10-19 J

Which of the following statements correctly describe atoms and elements? Select all that apply.

An element cannot be divided into simpler substances. An atom is considered a basic building block of matter.

X

Atomic symbol: the element symbol found in the periodic table

Which of the following statements correctly describe different types of energy? Select all that apply.

Changes in thermal energy are detected by measuring temperature changes. Chemical energy is a type of potential energy. The kinetic energy of an object is directly proportional to its mass.

Protons and neutrons

Comprise essentially all of the mass of an atom

Which of the following statements correctly describe the photoelectric effect? Select all that apply.

Current begins to flow immediately when light of the correct frequency shines on the metal plate. The kinetic energy of the electrons ejected from the metal depends on the frequency of the light used in the experiment.

Neutrons

Do not bear Coulombic charges

Which of the following statements correctly describe atomic line spectra? Select all that apply.

Each element has its own unique atomic line spectrum. Atomic line spectra include radiation outside the visible range of the electromagnetic spectrum. An atomic line spectrum arises from the emission of light of specific wavelengths.

Which of the following statements correctly describe the experimental findings that led to the characterization of the electron? Select all that apply.

Experiments with cathode rays led Thomson to propose that the electron was a negatively charged particle. The observation of cathode rays showed that electrons were common to all matter. Millikan used the charges on oil droplets to find the charge of the electron.

Which of the following statements correctly describe the Bohr model of the hydrogen atom? Select all that apply.

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.

Electrons

Reside outside the nucleus of the atom

The first hypothesis of Dalton's original atomic theory was that atoms, of which all matter consists, are tiny, indivisible particles and that, for a given element, all of the particles are identical. Which part(s) of this hypothesis was/were subsequently shown to be incorrect? Select all that apply.

That all atoms of a given element are identical. That atoms are indivisible. They are actually made up of subatomic particles.

Which of the following statements correctly describe the atomic number of an element? Select all that apply.

The atomic number is equal to the number of protons in the nucleus. Each element has its own unique atomic number.

How does the average atomic mass of an element compare to the mass number?

The average atomic mass is the average mass of a mixture of isotopes, whereas each isotope has its own mass number.

Energy is quantized. What does this mean?

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

In order for a current to flow in a photoelectric cell, a photon of light 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

The law of _________________ of energy states that energy can be neither created nor destroyed.

conservation

Rutherford conducted a famous experiment in which α particles were fired at a piece of gold foil. A few α particles were reflected by the foil, leading Rutherford to the conclusion that the atom contains a small, very dense region in which most of the atom's ___________ is concentrated. He called this central region the ____________ of the atom.

mass; nucleus

Which of the following statements correctly describe a photon? Select all that apply.

A photon is a particle of electromagnetic radiation. Matter cannot absorb or emit a fraction of a photon.

Which of the following options correctly describe isotopes? Select all that apply.

Isotopes have different numbers of neutrons. Isotopes of the same element have the same element symbols. Isotopes have similar chemical properties.

It is common to represent an element using the atomic symbol format XZAXZA. Select all the statements that correctly identify the components of this abbreviation.

The sum of protons and neutrons is given by A. A indicates the mass number of the element.

Which of the following correctly describe the two components of Maxwell's electromagnetic wave? Select all that apply.

The two wave components have the same wavelength and frequency. The wave consists of an oscillating magnetic field component. The wave consists of an oscillating electric field component.

Any two waves that meet as they travel through the same medium will interact. If the two waves are in phase their crests will coincide and they will exhibit _____ interference, producing a wave with a(n) _____ amplitude.

constructive, increased

Atoms, like all other matter, have specific energy levels within them. For an atom to absorb radiation, the energy of the radiation must match the energy _______________ between the two energy levels in the atoms.

gap

Rutherford's famous experiment involved bombarding a thin piece of __________ foil with ___________ particles, which were known to be heavy and positively charged. The pathway of these particles was tracked by allowing them to strike a fluorescent screen after interacting with the foil.

gold; alpha

atom

the smallest quantity of matter that still retains the properties of matter

Determine the wavelength of radiation emitted when the electron in a hydrogen atom moves from n = 4 to n = 1. In what region of the electromagnetic spectrum does this emission occur?

ultraviolet 97.3 nm

An electron in the n = 3 energy level of the hydrogen atom emits a photon with wavelength 656.27 nm. What is the change in energy of the electron, and to which energy level does it move?

ΔE = 3.03 × 10^-19 J It moves to n = 2.

An unknown element has two isotopes: one whose mass is 68.926 amu (60.00% abundance) and the other whose mass is 70.925 amu (40.00% abundance). The average atomic mass of the element is equal to _____.

69.73

850 nm

3.53 × 1014 s-1

Determine the frequency (in s−1) of radiation with a wavelength of 83.5 nm.

3.59 × 1015 s−1

Which of the following correctly defines the average atomic mass of an element?

The average of the masses of that element's naturally occurring isotopes weighted according to their abundance

Which of the following statements about protons are correct? Select all that apply.

The charge of a proton is opposite in sign to that of an electron. Protons account for all of the charge in an atom's nucleus. Protons are found in the nucleus of an atom.

Which of the following statements correctly describe subatomic particles? Select all that apply.

The electrons are located outside the nucleus of an atom. The mass of an electron is significantly smaller than the mass of a proton. Protons are positively charged.

A particular atom of an element is represented by the symbol 15/7 N. Which of the following options correctly interpret this symbol? Select all that apply.

The element contains 7 protons in its nucleus. The element contains 8 neutrons in its nucleus.

Which of the following statements correctly describes how energy is absorbed by an atom?

The energy of the absorbed radiation must match the difference between the two energy states of the atom.

In a photoelectric diode, no current will flow unless light of a certain minimum "threshold" frequency is used. Which of the following explains this observation correctly?

The energy of the photons of light must match or exceed the energy needed for electrons to break free from the metal.

Which of the following options correctly describe the mass number of an element? Select all that apply.

The mass number of an element is given the symbol A. The mass number is given by the sum of the protons and neutrons in the nucleus. The mass number is often written as a left superscript next to the atomic symbol.

Which of the following statements about subatomic particles are correct? Select all that apply.

The mass of a proton is similar to that of a neutron. The charge on a proton is equal in magnitude and opposite in sign to that of an electron.

Which of the following options correctly describe the way two waves can interact? Select all that apply.

When two waves that are in phase interact, constructive interference is observed. If the peaks of two waves coincide, a new wave with a larger amplitude will result.

Thomson's experiments with cathode rays determined that atoms contained even smaller particles called _____, which have a _____ charge.

electrons; negative

Any two waves that meet as they travel through the same medium will interact. If the two waves are out of phase their crests will not coincide and they will exhibit _____ interference, producing a wave with a(n) _____ amplitude.

destructive, decreased

According to the nuclear model, the atom is described as having a dense central _________, which contains the protons and____________. The ___________ are distributed within the surrounding space.

nucleus; neutrons; electrons

Each element has a unique number of ___________, which is called the atomic number. For an electrically neutral atom, this number is also equal to the number of ___________ present.

protons; electrons

Energy is not continuous, but is quantized 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