Atoms, The Nucleus And The Mole
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How are ions formed?
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By gaining or losing electrons
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By gaining or losing protons
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By beta decay
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By positron emission
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Chemistry students, assemble! Today we’ll be having a look at a number of different topics under the overall study of nuclear chemistry, including atoms, the nucleus and the mole. Do you have a firm enough grip on each of these topics? Take this quiz and find out!
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- 2.
What experiment resulted to the discovery of the nucleus?
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Gold foil (or alpha scattering) experiment
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Cathode ray tubes
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Oil drop experiment
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Mass spectroscopy
Correct Answer
A. Gold foil (or alpha scattering) experimentExplanation
The gold foil (or alpha scattering) experiment conducted by Ernest Rutherford resulted in the discovery of the nucleus. In this experiment, Rutherford bombarded a thin gold foil with alpha particles and observed their scattering patterns. He expected the alpha particles to pass straight through the foil or be slightly deflected, as per the prevailing model of the atom at the time. However, he observed that some alpha particles were deflected at large angles, and a few even bounced back. This led to the conclusion that the atom has a tiny, dense, and positively charged nucleus at its center, surrounded by mostly empty space.Rate this question:
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- 3.
Which of the following pairs of compounds could be used to explain the law of multiple proportions?
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H2O and H2O2
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CH4 and CO2
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NaCl and KCl
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SO3 and H2S
Correct Answer
A. H2O and H2O2Explanation
The law of multiple proportions states that when two elements combine to form different compounds, the ratio of the masses of one element that combines with a fixed mass of the other element can be expressed in small whole numbers. In the case of H2O and H2O2, both compounds involve the combination of hydrogen and oxygen, but in different ratios. H2O has a 2:16 ratio of hydrogen to oxygen, while H2O2 has a 2:32 ratio. These ratios can be simplified to 1:8 and 1:16 respectively, showing that the masses of oxygen that combine with a fixed mass of hydrogen are in small whole number ratios.Rate this question:
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- 4.
If you have 5g each of Li, Na, K, and Rb, for which element will you have the largest number of moles?
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Lithium
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Sodium
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Potassium
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Rubidium
Correct Answer
A. LithiumExplanation
Lithium will have the largest number of moles because it has the smallest molar mass among the given elements. Molar mass is the mass of one mole of a substance, and since the mass of lithium is the smallest, it will have the largest number of moles when compared to the other elements with larger molar masses.Rate this question:
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- 5.
How many electrons are in a magnesium-24 with a charge of 2+?
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10
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12
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14
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22
Correct Answer
A. 10Explanation
Magnesium-24 is an isotope of magnesium with a mass number of 24. The charge of 2+ indicates that the atom has lost two electrons. Since magnesium has an atomic number of 12, it normally has 12 electrons. However, with a charge of 2+, it means that two electrons have been removed, leaving behind 10 electrons. Therefore, the correct answer is 10.Rate this question:
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- 6.
Which of the following has an odd number of both protons and neutrons?
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Helium-4
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Lithium-7
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Boron-10
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Carbon-13
Correct Answer
A. Boron-10Explanation
Boron-10 has an odd number of both protons and neutrons. It has 5 protons and 5 neutrons, making a total of 10 nucleons. The other options have an even number of either protons or neutrons. Helium-4 has 2 protons and 2 neutrons, lithium-7 has 3 protons and 4 neutrons, and carbon-13 has 6 protons and 7 neutrons. Therefore, boron-10 is the only option that fits the criteria of having an odd number of both protons and neutrons.Rate this question:
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- 7.
Who discovered the charge to mass ratio for electrons?
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J.J. Thomson
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Ernest Rutherford
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John Dalton
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Robert Millikan
Correct Answer
A. J.J. ThomsonExplanation
J.J. Thomson is credited with discovering the charge to mass ratio for electrons. He conducted experiments using cathode ray tubes and observed the deflection of the rays in the presence of electric and magnetic fields. Through his experiments, Thomson determined that the ratio of the charge of an electron to its mass is constant, regardless of the type of gas used in the cathode ray tube. This discovery laid the foundation for our understanding of the fundamental properties of electrons and their role in atomic structure.Rate this question:
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- 8.
In positron emission, what is the resulting change in the nucleus?
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Atomic number increases by 1.
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Atomic number decreases by 1.
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Atomic number decreases by 2.
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Atomic number stays the same.
Correct Answer
A. Atomic number decreases by 1.Explanation
In positron emission, a proton in the nucleus is converted into a neutron, resulting in a decrease in the atomic number by 1. This occurs because a positron, which is a positively charged particle, is emitted from the nucleus. The positron carries away one positive charge, causing the atomic number to decrease.Rate this question:
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- 9.
If you have three times the mass of carbon as you have helium, which of the following is true?
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You have nearly equal numbers of carbon atoms as helium atoms.
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You have more atoms of carbon.
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You have more atoms of helium.
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You cannot know a relationship between carbon atoms and helium atoms.
Correct Answer
A. You have nearly equal numbers of carbon atoms as helium atoms.Explanation
If you have three times the mass of carbon as you have helium, it means that the mass of carbon is three times greater than the mass of helium. Since the atomic mass of carbon is 12.01 g/mol and the atomic mass of helium is 4.00 g/mol, this implies that the number of carbon atoms is approximately equal to the number of helium atoms. This is because the mass of an element is directly proportional to the number of atoms present. Therefore, the correct answer is that you have nearly equal numbers of carbon atoms as helium atoms.Rate this question:
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Current Version
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Oct 19, 2023Quiz Edited by
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Sep 04, 2009Quiz Created by
John Thompson
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