Developing a Nuclear Model 2

Rutherford's famous experiment involved bombarding a ____ 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.

Blank 1: gold, Au, or thin gold Blank 2: alpha

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.

Blank 1: nucleus or core Blank 2: neutrons or neutron Blank 3: electrons

Match each component of the atom with the correct description. Nucleus Electron Proton Neutron Small region that contains almost all of the mass of an atom Negatively charged particle Positively charged particle found within the center of the atom Uncharged dense particle located in the center of the atom

Nucleus: Small region that contains almost all of the mass of an atom Electron: Negatively charged particle Proton: Positively charged particle found within the center of the atom Neutron: Uncharged dense particle located in the center of the atom

Match each particle or set of particles with the correct description. Protons and neutrons Electrons and protons Electrons Neutrons Comprise essentially all of the mass of an atom The subatomic particles that bear Coulombic charges Reside outside the nucleus of the atom Do not bear Coulombic charges

Protons and neutrons: Comprise essentially all of the mass of an atom Electrons and protons: The subatomic particles that bear Coulombic charges Electrons: Reside outside the nucleus of the atom Neutrons: Do not bear Coulombic charges

Which of the following statements correctly describe atoms and elements? Select all that apply. a. An atom is considered a basic building block of matter. b. An atom can be divided into smaller particles that exhibit properties identical to those of the original atom. c. The term "atom" is another word for "element." d. An element cannot be divided into simpler substances.

a. An atom is considered a basic building block of matter. d. An element cannot be divided into simpler substances. Reason: The subatomic particles in an atom do not have the same physical properties as the atom. Reason: An atom is the smallest quantity of matter that still retains the properties of matter, whereas an element is a substance that cannot be broken down into simpler substances. The two terms are not synonyms.

Which of the following statements correctly describe the experimental findings that led to the characterization of the electron? Select all that apply. a. Experiments with cathode rays led Thomson to propose that the electron was a negatively charged particle. b. Experiments with cathode rays revealed that electrons are found in the nucleus of the atom. c. The cathode rays produced by different elements differed, indicating that electrons still retain the properties of the atom they come from. d. The observation of cathode rays showed that electrons were common to all matter. e. Millikan used the charges on oil droplets to find the charge of the electron.

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

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. a. That atoms are indivisible. They are actually made up of subatomic particles. b. That all atoms of a given element are identical. c. That all matter consists of atoms. Some matter consists of molecules. d. That atoms are tiny. Atoms are actually very large.

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

Which of the following statements about subatomic particles are correct? Select all that apply. a. The charge on a proton is equal in magnitude and opposite in sign to that of an electron. b. The mass of a neutron is slightly greater than that of an electron. c. Neutrons and protons are the only charged subatomic particles. d. The mass of a proton is similar to that of a neutron.

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

Thomson's experiments with cathode rays determined that atoms contained even smaller particles called _____, which have a _____ charge. a. electrons; negative b. protons; positive c. electrons; positive d. protons; negative

a. electrons; negative Reason: Cathode rays were found to consist of electrons/ negatively charged particles

Which of the following statements about protons are correct? Select all that apply. a. The mass of a proton is approximately equal to that of an electron. b. The charge of a proton is opposite in sign to that of an electron. c. The charge of a proton is approximately 2000 times that of an electron. d. Protons are found in the nucleus of an atom. e. Protons account for all of the charge in an atom's nucleus.

b. The charge of a proton is opposite in sign to that of an electron. d. Protons are found in the nucleus of an atom. e. Protons account for all of the charge in an atom's nucleus. Reason: The mass of a proton is approximately 2000 times that of an electron. Reason: The charges of a proton and an electron are equal in magnitude, opposite in sign. The mass of a proton is approximately 2000 times that of an electron. Reason: The nucleus of an atom is positively charged, and all of that charge comes from protons.

Which of the following statements correctly describe subatomic particles? Select all that apply. a. The charge on a neutron is equal but opposite to the charge on a proton. b. The mass of an electron is significantly smaller than the mass of a proton. c. The electrons are located outside the nucleus of an atom.' d. Protons are positively charged. e. A neutron is much heavier than a proton.

b. The mass of an electron is significantly smaller than the mass of a proton. c. The electrons are located outside the nucleus of an atom.' d. Protons are positively charged. Reason: A neutron has zero electrical charge. Reason: The mass of a neutron is very close to the mass of a proton.

Which of the following correctly describe atomic structure? Select all that apply. a. The number of neutrons in the nucleus equals the number of protons. b. The protons and neutrons together comprise most of the mass of the atom. c. The electrons comprise the nucleus of the atom. d. The nucleus comprises a very small fraction of the total volume of the atom. e. The number of protons equals the number of electrons in a neutral atom.

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

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) ______. a. proton; neutron b. proton; electron c. neutron; electron d. electron; proton

b. proton; electron

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

blank 1: mass blank 2: nucleus

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. a. The deflections of the α particles indicated that the central core of the atom is negatively charged. b. All α particles passed straight through the foil, indicating that an atom is composed of scattered positive and negative charges. c. A few α particles showed major deflections, indicating the presence of a dense central core within the atom. d. Most α particles passed straight through the foil, implying that the atom consists largely of empty space.

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

Which of the following statements correctly describe Rutherford's experiment? Select all that apply. a. Rutherford's experiment confirmed that the atom is a solid sphere. b. The deflection of the α particles showed that the nucleus of the atom was negatively charged. c. This experiment used α particles to probe atomic structure. d. An α particle was known at this time to be positively charged. e. The pathway followed by the α particles was tracked using a fluorescent zinc-sulfide screen.

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

Which best describes the relative masses of the subatomic particles? a. electron ≈ proton > neutron b. electron ≈ proton < neutron c. electron > proton > neutron d. electron < proton ≈ neutron

d. electron < proton ≈ neutron Reason: The mass of an electron is thousands of times smaller than those of protons and neutrons.