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Test Prep

# Test Prep

### Multiple Choice

#### 22.1The Structure of the Atom

1.
If electrons are negatively charged and the nucleus is positively charged, why do they not attract and collide with each other?
1. The pull from the nucleus provides a centrifugal force, which is not strong enough to draw the electrons into the nucleus.
2. The pull from the nucleus provides a centripetal force, which is not strong enough to draw the electrons into the nucleus.
3. The pull from the nucleus provides a helical motion.
4. The pull from the nucleus provides a cycloid motion.

#### 22.4Nuclear Fission and Fusion

2.

If a nucleus elongates due to a neutron strike, which of the following forces will decrease?

1. Nuclear force between neutrons only
2. Coulomb force between protons only
3. Strong nuclear force between all nucleons and Coulomb force between protons, but the strong force will decrease more
4. Strong nuclear force between neutrons and Coulomb force between protons, but Coulomb force will decrease more

#### 22.1The Structure of the Atom

3.

Why do Bohr’s calculations for electron energies not work for all atoms?

1. In atoms with more than one electron is an atomic shell, the electrons will interact. That requires a more complex formula than Bohr’s calculations accounted for.
2. In atoms with 10 or more electorns in an atomic shell, the electrons will interact. That requires a more complex formula than Bohr’s calculations accounted for.
3. In atoms with more than one electron in an atomic shell, the electrons will not interact. That requires a more complex formula than Bohr’s calculations accounted for.
4. In atoms with 10 or more electrons in an atomic shell, the electrons will not interact. That requires a more complex formula than Bohr’s calculations accounted for.

4.
Does transmutation occur within chemical reactions?
1. no
2. yes

5.
How does the radioactive activity of a sample change with time?
1. The radioactive activity decreases exponentially.
2. The radioactive activity undergoes linear decay.
3. The radioactive activity undergoes logarithmic decay.
4. The radioactive activity will not change with time.

#### 22.4Nuclear Fission and Fusion

6.
Why does fission of heavy nuclei result in the release of neutrons?
1. Heavy nuclei require more neutrons to achieve stability.
2. Heavy nuclei require more neutrons to balance charge.
3. Light nuclei require more neutrons to achieve stability.
4. Light nuclei require more neutrons to balance charge.

7.
Why is radioactive iodine used to monitor the thyroid?
1. Radioactive iodine can be used by the thyroid while absorbing information about the thyroid.
2. Radioactive iodine can be used by the thyroid while emitting information about the thyroid.
3. Radioactive iodine can be secreted by the thyroid while absorbing information about the thyroid.
4. Radioactive iodine can be secreted by the thyroid while emitting information about the thyroid.

### Extended Response

#### 22.1The Structure of the Atom

8.
Compare the standing wavelength of an $n=2$ orbital to the standing wavelength of an $n=4$ orbital.
1. The standing wavelength of an $n=2$ orbital is greater than the standing wavelength of an $n=4$ orbital.
2. The standing wavelength of an $n=2$ orbital is less than the standing wavelength of an $n=4$ orbital.
3. There is no relation between the standing wavelength of an $n=2$ orbital and the standing wavelength of an $n=4$ orbital.
4. The standing wavelength of an $n=2$ orbital is the same as the standing wavelength of an$n=4$ orbital.
9.
Describe the shape of the electron cloud, based on total energy levels, for an atom with electrons in multiple orbital states.
1. There are multiple regions of high electron probability of various shapes surrounding the nucleus.
2. There is a single solid spherical region of high electron probability surrounding the nucleus.
3. There are multiple concentric shells of high electron probability surrounding the nucleus.
4. There is a single spherical shell of high electron probability surrounding the nucleus.

10.
How did Becquerel’s observations of pitchblende imply the existence of radioactivity?
1. A chemical reaction occurred on the photographic plate without any external source of energy.
2. Bright spots appeared on the photographic plate due to an external source of energy.
3. Energy from the Sun was absorbed by the pitchblende and reflected onto the photographic plate.
4. Dark spots appeared on the photographic plate due to an external source of energy.

#### 22.4Nuclear Fission and Fusion

11.
Describe the potential energy of two nuclei as they approach each other.
1. The potential energy will decrease as the nuclei are brought together and then rapidly increase once a minimum is reached.
2. The potential energy will decrease as the nuclei are brought together.
3. The potential energy will increase as the nuclei are brought together.
4. The potential energy will increase as the nuclei are brought together and then rapidly decrease once a maximum is reached.