AnswersFL-2002110-MJ Comprehensive Science 3 Advanced A - FlexAtomic Theory

Atomic Theory Answers

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Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below.What experimental evidence led scientists to change from the previous model to this one?

Question illustration
A
A few of the positive particles aimed at a gold foil seemed to bounce back.
B
The colors of light emitted from heated atoms had very specific energies.
C
Experiments with water vapor showed that elements combine in specific proportions.
D
Cathode rays were bent in the same way whenever a magnet was brought near them.
2
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What new characteristic did John Dalton add to the model of the atom?

A
An atom is a round, solid mass.
B
An atom has a massive, positive center.
C
An atom is made up of smaller particles.
D
An atom can join with other kinds of atoms.
3

Oppositely charged objects attract each other. This attraction holds electrons in atoms and holds atoms to one another in many compounds. However, Ernest Rutherford’s model of the atom failed to explain why electrons were not pulled into the atomic nucleus by this attraction.What change to the atomic model helped solve the problem seen in Rutherford’s model?

A
Bohr’s work with atomic spectra led him to say that the electrons were limited to existing in certain energy levels, like standing on the rungs of a ladder.
B
Bohr’s work with cathode rays led him to say that the electrons were located within the mass of positive material, like plums in a pudding.
C
Thomson’s work with cathode rays led him to say that the electrons were located within the mass of positive material, like plums in a pudding.
D
Thomson’s work with atomic spectra led him to say that the electrons were limited to existing in certain energy levels, like standing on the rungs of a ladder.
4

The modern model of the atom describes electrons in a little less specific detail than earlier models did. Why is it that being less sure about the placement of electrons in an atom is actually an improvement over earlier models?

A
Electrons do not follow specific paths, so describing the area where an electron is likely to be is more scientifically accurate.
B
Electrons were thought to be negatively charged, but now scientists know that their charge depends on their energy level.
C
The modern model is based on mathematical equations, so the results become less clear when the decimals are rounded.
D
The position of electrons in atomic models has changed so much that it is better to have a less specific model than to be wrong again.
5

A cathode ray tube is made of glass with a small amount of some kind of gas in it. It has metal electrodes at each end to pick up an electric current. The electrodes are named "positive” and "negative."What are one of the main uses of this device ?

A
to speed up the flow of current flowing through a wire
B
to examine a beam of charged particles
C
to magnetize different atoms within a space
D
to change the strength of a proton within an atom
6

Which statement describes one feature of Rutherford’s model of the atom?

A
The atom is mostly empty space.
B
The atom cannot be divided into smaller particles.
C
Electron clouds are regions where electrons are likely to be found.
D
The electrons are located within the positive material of the nucleus.
7

Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below.

Question illustration
A
A few of the positive particles aimed at a gold foil seemed to bounce back.
B
The colors of light emitted from heated atoms had very specific energies.
C
Equations were used to identify regions around the nucleus where electrons would likely be.
D
Cathode rays were bent in the same way whenever a magnet was brought near them.
8

Rutherford tracked the motion of tiny, positively charged particles shot through a thin sheet of gold foil. Some particles traveled in a straight line and some were deflected at different angles.Which statement best describes what Rutherford concluded from the motion of the particles?

A
Some particles traveled through empty parts of the atoms and some particles were deflected by neutrons.
B
Some particles traveled through empty parts of the atom and some particles were deflected by electrons.
C
Some particles traveled through empty parts of the atom and some particles were deflected by the orbits of atoms.
D
Some particles traveled through empty parts of the atom and some particles were deflected by small areas of high-density positive charge in atoms.
9

The atomic models after Dalton’s time included ideas about the atomic structure.Which atomic model that shows the atomic structure is missing from this set?

Question illustration
A
Niels Bohr’s model
B
Schrödinger’s model
C
Rutherford’s model
D
Thomson’s model
10

Which statement belongs to Dalton’s atomic theory?

A
Atoms have a massive, positively charged center.
B
Atoms cannot be created or destroyed.
C
Atoms can be broken down into smaller pieces.
D
Electrons are located in energy levels outside of the nucleus.

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