Atomic Structure And Radioactivity
Review on the parts of the atom, atomic number, mass number and radioactivity.
Questions and Answers
- 1.
This subatomic particle has a negative charge.
- A.
Neutron
- B.
Proton
- C.
Electron
Correct Answer
C. ElectronExplanation
An electron is a subatomic particle that carries a negative charge. It is found outside the nucleus of an atom and is involved in chemical reactions and electricity. Neutrons and protons, on the other hand, carry no charge or a positive charge, respectively. Therefore, the correct answer is electron.Rate this question:
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- 2.
The total number of these determines the mass number.
- A.
Protons and electrons
- B.
Neutrons and electrons
- C.
Neutrons and protons
Correct Answer
C. Neutrons and protonsExplanation
The mass number of an atom is determined by the total number of neutrons and protons in its nucleus. Protons have a positive charge and are responsible for the atom's identity, while neutrons have no charge and contribute to the mass of the atom. Electrons, on the other hand, have a negative charge and are found in the electron cloud surrounding the nucleus, but they do not contribute significantly to the mass of the atom. Therefore, the correct answer is "neutrons and protons."Rate this question:
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- 3.
This particle has a mass that is about 1800 times smaller than the other two.
- A.
Electron
- B.
Proton
- C.
Neutron
Correct Answer
A. ElectronExplanation
The electron is the correct answer because it has a mass that is about 1800 times smaller than the other two particles, the proton and neutron. This means that the electron is much lighter compared to the proton and neutron, making it the smallest in terms of mass.Rate this question:
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- 4.
Isotopes of the same element have different numbers of these particles.
- A.
Protons
- B.
Neutrons
- C.
Electrons
Correct Answer
B. NeutronsExplanation
Isotopes of the same element have different numbers of neutrons. Protons and electrons are always the same in an element, but isotopes can have varying numbers of neutrons, which affects their atomic mass.Rate this question:
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- 5.
The number of these particles determines the atomic number
- A.
Protons
- B.
Protons and neutrons
- C.
Protons and electrons
- D.
Neutrons
- E.
Neutrons and electrons
Correct Answer
A. ProtonsExplanation
The atomic number of an element is determined by the number of protons in its nucleus. Protons are positively charged particles found in the nucleus of an atom. Each element has a unique number of protons, which is its atomic number. Therefore, the number of protons in an atom determines its atomic number.Rate this question:
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- 6.
Found in the nucleus
- A.
Electrons and neutrons
- B.
Protons, electrons and neutrons
- C.
Protons and neutrons
- D.
Electrons and protons
Correct Answer
C. Protons and neutronsExplanation
Protons and neutrons are subatomic particles found in the nucleus of an atom. Electrons are not found in the nucleus, but rather orbit around it in electron shells. Therefore, the correct answer is "protons and neutrons".Rate this question:
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- 7.
Has a positive charge
- A.
Electrons
- B.
Neutrons
- C.
Protons
Correct Answer
C. ProtonsExplanation
Protons are subatomic particles found in the nucleus of an atom and they have a positive charge. Electrons, on the other hand, have a negative charge and are found orbiting the nucleus. Neutrons have no charge and are also found in the nucleus. Therefore, the only particle mentioned in the question that has a positive charge is the proton.Rate this question:
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- 8.
Has no charge
- A.
Electrons
- B.
Neutrons
- C.
Protons
Correct Answer
B. NeutronsExplanation
Neutrons are subatomic particles found in the nucleus of an atom. Unlike electrons, which have a negative charge, and protons, which have a positive charge, neutrons have no charge. This means that they are electrically neutral. Neutrons play a crucial role in determining the stability and properties of an atom, as they help to balance the positive charge of the protons in the nucleus.Rate this question:
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- 9.
Has a mass of about 1 amu
- A.
Protons
- B.
Electrons
- C.
Neutrons
- D.
Protons and electrons
- E.
Neutrons and electrons
- F.
Protons and neutrons
Correct Answer
F. Protons and neutronsExplanation
Protons and neutrons are subatomic particles found in the nucleus of an atom. They both have a mass of approximately 1 atomic mass unit (amu). Electrons, on the other hand, have a much smaller mass compared to protons and neutrons. Therefore, the statement "Has a mass of about 1 amu" is best explained by the presence of protons and neutrons in an atom.Rate this question:
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- 10.
The number 14 is the:
- A.
Mass number
- B.
Atomic number
- C.
Average atomic mass
Correct Answer
B. Atomic numberExplanation
The atomic number represents the number of protons in an atom's nucleus. It determines the element's identity and its position on the periodic table. In this case, the number 14 is referring to the atomic number, not the mass number or average atomic mass.Rate this question:
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- 11.
The 28.09 is the:
- A.
Atomic number
- B.
Mass number
- C.
Average atomic mass
Correct Answer
C. Average atomic massExplanation
The given answer, average atomic mass, refers to the weighted average of the masses of all the naturally occurring isotopes of an element. It takes into account the abundance of each isotope and is usually expressed in atomic mass units (amu). The average atomic mass is an important quantity as it helps in identifying and characterizing different isotopes of an element, which have varying masses due to different numbers of neutrons.Rate this question:
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- 12.
You will need a periodic table for this one:A neutral atom of Pb-208 would have ? protons.
- A.
82
- B.
208
- C.
126
Correct Answer
A. 82Explanation
A neutral atom of Pb-208 would have 82 protons. The atomic number of an element represents the number of protons in its nucleus. Since the atom is neutral, it means that the number of protons is equal to the number of electrons. Therefore, for a neutral atom of Pb-208, the number of protons would be 82.Rate this question:
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- 13.
A neutral atom of Pb-208 would have ? neutrons.
- A.
208
- B.
82
- C.
126
Correct Answer
C. 126Explanation
The atomic number of an element represents the number of protons in the nucleus of an atom. In this case, the atomic number of lead (Pb) is 82. The atomic mass of an element represents the sum of the protons and neutrons in the nucleus. Since the atomic mass of Pb-208 is 208, we can subtract the atomic number from the atomic mass to find the number of neutrons. Therefore, Pb-208 would have 126 neutrons.Rate this question:
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- 14.
A neutral atom of Pb-208 would have ? electrons.
- A.
208
- B.
82
- C.
126
Correct Answer
B. 82Explanation
The atomic number of an element represents the number of protons in the nucleus of an atom. Since a neutral atom has an equal number of protons and electrons, the number of electrons in a neutral atom of Pb-208 would be equal to its atomic number, which is 82.Rate this question:
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- 15.
Chlorine has two naturally occurring isotopes, Cl-35 with a relative abundance of 75.77% and Cl-37 with a relative abundance of 24.23%. On a piece of paper, work out the average atomic mass of chlorine rounded to the nearest 1/100th of an amu. Check out the explanation if you get it wrong!
Correct Answer
35.48Explanation
35 x .7577 37 x .2423
Then add the two answers together, round to nearest 1/100th.Rate this question:
- 16.
Radium-211 has a half-life of 13 seconds. If you started with 600 mg of Ra-211, how many seconds would it take until you only had 18.75 mg?
Correct Answer
65Explanation
Make a table and start dividing 600 in half, keeping track of how many times it takes until you get to 18.75. This would be the number of half-lives. Each one of those takes 13 seconds. Do the math!Rate this question:
- 17.
The half-life of Radium-229 is 4 minutes. What was the original mass (to the nearest 1/100th of a gram) of Ra-229 if .32 g remains after 12 minutes?
Correct Answer
2.56Explanation
12 minutes / 3 minutes give the number of half-lives that have gone by. Working backwards, double the amount of Ra-229 until that number of half-lives is reached.Rate this question:
- 18.
Radium-226 has a half-life of 1600 years. What percentage would be left (to the nearest 1/100th of a percent) after 6400 years? Put a percent sign on your answer!
Correct Answer
6.25%Explanation
6400/1600 gives the number of half-lives. Start with 100% and cut in half that many of times.Rate this question:
- 19.
In beta decay, a neutron undergoes a change into a ? and then an electron is ejected from the nucleus.
Correct Answer
protonExplanation
In beta decay, a neutron undergoes a change into a proton and then an electron is ejected from the nucleus. This process occurs when a neutron in the nucleus of an atom transforms into a proton, increasing the atomic number by one. As a result, to maintain charge neutrality, an electron is emitted from the nucleus. This process is a common type of radioactive decay and is responsible for the emission of beta particles.Rate this question:
- 20.
In both fission and fusion, a small amount of ? is converted into energy.
Correct Answer
massExplanation
In both fission and fusion, a small amount of mass is converted into energy. This is based on Einstein's famous equation E=mc², which states that energy (E) is equal to mass (m) times the speed of light (c) squared. In nuclear fission, the nucleus of an atom is split into two smaller nuclei, releasing energy in the process. In nuclear fusion, two smaller nuclei combine to form a larger nucleus, also releasing energy. In both cases, a small amount of mass is converted into a large amount of energy, as predicted by Einstein's equation.Rate this question:
- 21.
In nuclear fusion, atoms of hydrogen are combined under intense heat and pressure to form ?
Correct Answer
heliumExplanation
In nuclear fusion, atoms of hydrogen are combined under intense heat and pressure to form helium. This process occurs in the core of stars, including our Sun, where the high temperatures and pressures cause hydrogen atoms to fuse together, releasing a tremendous amount of energy. As the hydrogen atoms combine, they form helium atoms, and this fusion reaction is the fundamental process that powers stars, including the Sun, by converting hydrogen into helium and releasing an enormous amount of energy in the process.Rate this question:
- 22.
In nuclear fission, a ? strikes an atom of uranium (or plutonium) causing it to split.
Correct Answer
neutronExplanation
In nuclear fission, a neutron strikes an atom of uranium (or plutonium) causing it to split. Neutrons are uncharged particles that can easily penetrate the nucleus of an atom. When a neutron collides with a uranium or plutonium atom, it causes the nucleus to become unstable and split into two smaller nuclei, releasing a large amount of energy in the process. This is the basis of nuclear power and atomic bombs.Rate this question:
- 23.
Isotopes of the same element have the same mass number but different atomic numbers.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
This is backwards, they have the same atomic number (making them the same element) but have different mass numbers (due to the different numbers of neutrons).Rate this question:
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- 24.
Over 99% of the mass of an atom is located within the tiny nucleus.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the nucleus of an atom contains protons and neutrons, which have a much greater mass compared to the electrons that orbit around the nucleus. The electrons have negligible mass in comparison to the protons and neutrons. Therefore, the majority of the mass of an atom is concentrated within its nucleus.Rate this question:
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- 25.
Most of an atom's volume is empty space.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Atoms are made up of a nucleus, which contains protons and neutrons, and electrons that orbit around the nucleus. The nucleus is extremely small compared to the overall size of the atom, meaning that most of the atom's volume is empty space. The electrons occupy a relatively large amount of space around the nucleus, but they are so small and light that the empty space between them and the nucleus is much larger. Therefore, it can be concluded that most of an atom's volume is indeed empty space.Rate this question:
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- 26.
The atomic number of an element is found by averaging the mass numbers of the isotopes and also takes into consideration the relative abundance of each isotope.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The atomic number is the number of protons. If the statement had referred to average atomic mass, it would have been true.Rate this question:
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- 27.
The nucleus of an atom has no charge, it is neutral.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Since the nucleus is made of + protons and neutrons with no charge, the nucleus has a positive charge.Rate this question:
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- 28.
In alpha decay, the nucleus ejects a particle that has two protons and two neutrons.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle, which consists of two protons and two neutrons. This process reduces the atomic number by two and the mass number by four. Therefore, the statement that in alpha decay, the nucleus ejects a particle that has two protons and two neutrons is true.Rate this question:
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- 29.
In alpha decay, the atomic number decreases by 4 and the mass number decreases by 2.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
It is the other way around, the mass number decreases by 4 and the atomic number decreases by 2.Rate this question:
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- 30.
The radium nucleus here would be called:
- A.
An alpha particle
- B.
The daughter nucleus
- C.
The parent nucleus
Correct Answer
C. The parent nucleusExplanation
The correct answer is "the parent nucleus" because in the context of radioactive decay, the radium nucleus is the original or parent nucleus that undergoes decay to produce a new nucleus, which is called the daughter nucleus. The term "alpha particle" refers to a specific type of particle emitted during alpha decay, but it does not describe the radium nucleus itself.Rate this question:
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- 31.
The helium nucleus here would be called:
- A.
An alpha particle
- B.
The daughter nucleus
- C.
The parent nucleus
Correct Answer
A. An alpha particleExplanation
The helium nucleus is called an alpha particle because it consists of two protons and two neutrons, which is the same composition as a helium atom. It is often emitted during radioactive decay and is highly ionizing due to its double positive charge. The terms "daughter nucleus" and "parent nucleus" refer to the products of radioactive decay, with the parent nucleus being the original radioactive atom and the daughter nucleus being the resulting atom after decay.Rate this question:
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- 32.
Which of the following is the best definition for half-life?
- A.
Half of the time that it takes for the radioactive atoms to decay
- B.
The time it takes for half of the radioactive atoms to decay
- C.
The time it takes for half of a radioactive atom to decay
- D.
Half of the time it takes for half of the radioactive atoms to decay
Correct Answer
B. The time it takes for half of the radioactive atoms to decayExplanation
The half-life of a radioactive substance refers to the time it takes for half of the atoms in a sample to decay. This means that after one half-life, half of the original radioactive atoms will have decayed, and after two half-lives, three-quarters of the original atoms will have decayed. Therefore, the best definition for half-life is "The time it takes for half of the radioactive atoms to decay."Rate this question:
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- 33.
The very last symbol above represents:
- A.
The daughter nucleus
- B.
An alpha particle
- C.
A beta particle
- D.
A neutron
Correct Answer
C. A beta particleExplanation
The very last symbol above represents a beta particle. Beta particles are high-energy electrons or positrons that are emitted during certain types of radioactive decay. They have a negative charge and are much smaller than alpha particles, which are represented by two protons and two neutrons. Neutrons are neutral particles and are not represented by a symbol in the given options. Therefore, the correct answer is a beta particle.Rate this question:
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- 34.
How did the atomic number increase by one?
- A.
A neutron changed into a proton
- B.
A proton was captured by the carbon
- C.
An electron was changed into a proton
- D.
A beta particle was captured by the nitrogen
Correct Answer
A. A neutron changed into a protonExplanation
The atomic number represents the number of protons in an atom's nucleus. In this case, the atomic number increased by one, indicating that an additional proton was added to the nucleus. This suggests that a neutron, which has no charge, underwent a transformation and converted into a proton, which has a positive charge. This process is known as beta decay, where a neutron decays into a proton, releasing a beta particle (an electron) in the process.Rate this question:
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- 35.
Which answer is closest to the half-life of the parent shown here?
- A.
5730 years
- B.
45 seconds
- C.
82 minutes
- D.
1.5 years
Correct Answer
A. 5730 yearsExplanation
This is carbon-14, used for dating objects that were once alive. We spent a period going over its half-life and how it was used by scientists.Rate this question:
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- 36.
This picture most closely shows:
- A.
Alpha decay
- B.
Beta decay
- C.
Neutron capture
- D.
Nuclear fission
- E.
Nuclear fusion
Correct Answer
D. Nuclear fissionExplanation
The picture most closely represents nuclear fission because it shows the splitting of a large atomic nucleus into two smaller nuclei, releasing a large amount of energy. This process is characteristic of nuclear fission, where the nucleus of an atom is split into two smaller nuclei, usually through the absorption of a neutron. This is different from alpha decay, beta decay, neutron capture, and nuclear fusion, which involve different processes and reactions.Rate this question:
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- 37.
The small white circles represent:
- A.
Neutrons
- B.
Alpha particles
- C.
Beta particles
- D.
Protons
- E.
Electrons
Correct Answer
A. NeutronsExplanation
The small white circles in the given diagram represent neutrons. Neutrons are subatomic particles that have no charge and are found in the nucleus of an atom. They are responsible for stabilizing the nucleus and determining the isotope of an element. In the diagram, the other particles such as alpha particles, beta particles, protons, and electrons are not represented by the small white circles.Rate this question:
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