Periodic Trends - GRE Subject Test: Chemistry
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Which of the given atoms has the smallest atomic radius?
Which of the given atoms has the smallest atomic radius?
Nitrogen, phosphorous, antimony, and bismuth are all in the same group (column) of the periodic table.
The atomic radius increases from the top of a group to the bottom, due to increased principle shell number (n). As one travels down a group, another s shell is added, meaning that electrons are added in another orbit farther from the nucleus. This serves to increase the atomic radius of the atom.
Nitrogen, phosphorous, antimony, and bismuth are all in the same group (column) of the periodic table.
The atomic radius increases from the top of a group to the bottom, due to increased principle shell number (n). As one travels down a group, another s shell is added, meaning that electrons are added in another orbit farther from the nucleus. This serves to increase the atomic radius of the atom.
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Which element would you expect to have the highest first ionization energy?
Which element would you expect to have the highest first ionization energy?
Ionization energy is a property of an atom or ion that describes the lowest energy needed to remove a electron from it in the ground state.
Ionization energy increases up and to the right on the periodic table. Because fluorine is located furthest to the top right on the periodic table in group 7A, it will have the highest first ionization energy.
Ionization energy is a property of an atom or ion that describes the lowest energy needed to remove a electron from it in the ground state.
Ionization energy increases up and to the right on the periodic table. Because fluorine is located furthest to the top right on the periodic table in group 7A, it will have the highest first ionization energy.
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Which element would you expect to have the highest first ionization energy?
Which element would you expect to have the highest first ionization energy?
Ionization energy is a property of an atom or ion that describes the lowest energy needed to remove a electron from it in the ground state.
Ionization energy increases up and to the right on the periodic table. All the elements listed are either lower than or further to the left on the periodic table than chlorine, therefore chlorine has the highest ionization energy.
Ionization energy is a property of an atom or ion that describes the lowest energy needed to remove a electron from it in the ground state.
Ionization energy increases up and to the right on the periodic table. All the elements listed are either lower than or further to the left on the periodic table than chlorine, therefore chlorine has the highest ionization energy.
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Which element would experience the greatest energy loss when a neutral atom in the gaseous phase gains one additional electron?
Which element would experience the greatest energy loss when a neutral atom in the gaseous phase gains one additional electron?
This question refers to electron affinity, which is defined as the energy given off when a neutral atom in the gas phase gains an extra electron.

Electron affinity increases for elements towards the top and right of the periodic table, so the elements in the top right lose the most energy when gaining an electron. Another way of thinking is that they lose energy, but gain stability. Of the available answers, the element to the most upper right of the periodic table is fluorine.
This question refers to electron affinity, which is defined as the energy given off when a neutral atom in the gas phase gains an extra electron.
Electron affinity increases for elements towards the top and right of the periodic table, so the elements in the top right lose the most energy when gaining an electron. Another way of thinking is that they lose energy, but gain stability. Of the available answers, the element to the most upper right of the periodic table is fluorine.
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Which element would you expect to have the highest first ionization energy?
Which element would you expect to have the highest first ionization energy?
Ionization energy is a property of an atom that describes the lowest energy needed to remove a electron from its valence shell in the ground state.
Ionization energy increases up and to the right on the periodic table. All the elements listed are halogens located in group 7A of the periodic table. Because fluorine is located at the top of the periodic table in group 7A, it will have the highest first ionization energy. Ionization energy can be though of as the inverse of atomic radius. That is, the closer the valence shell of electrons is to the nucleus, the larger the magnitude of electric attractive force, and thus, the more energy is required to strip that electron.
Ionization energy is a property of an atom that describes the lowest energy needed to remove a electron from its valence shell in the ground state.
Ionization energy increases up and to the right on the periodic table. All the elements listed are halogens located in group 7A of the periodic table. Because fluorine is located at the top of the periodic table in group 7A, it will have the highest first ionization energy. Ionization energy can be though of as the inverse of atomic radius. That is, the closer the valence shell of electrons is to the nucleus, the larger the magnitude of electric attractive force, and thus, the more energy is required to strip that electron.
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Which element would you expect to have the highest first ionization energy?
Which element would you expect to have the highest first ionization energy?
Ionization energy is a property of an atom or ion that describes the lowest energy needed to remove a electron from it in the ground state.
Ionization energy increases up and to the right on the periodic table. Because oxygen is the highest and rightmost element of those listed, it will have the highest first ionization energy. Ionization energy can be though of as the inverse of atomic radius. That is, the closer the valence shell of electrons is to the nucleus, the larger the magnitude of electric attractive force, and thus, the more energy is required to strip that electron.
Ionization energy is a property of an atom or ion that describes the lowest energy needed to remove a electron from it in the ground state.
Ionization energy increases up and to the right on the periodic table. Because oxygen is the highest and rightmost element of those listed, it will have the highest first ionization energy. Ionization energy can be though of as the inverse of atomic radius. That is, the closer the valence shell of electrons is to the nucleus, the larger the magnitude of electric attractive force, and thus, the more energy is required to strip that electron.
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Which of the given atoms has the largest atomic radius?
Which of the given atoms has the largest atomic radius?
Lithium, boron, oxygen, and neon are all in the same row (period) of the periodic table.
The atomic radius decreases from left to right along a period due to increased effective nuclear force. From left to right the atomic number increases, indicating that more protons are added. The addition of protons increases the positive charge in the nucleus, pulling in the outer electrons by increasing the effective nuclear force, decreasing the radius.
In math terms, we can equate effective nuclear force using the force equation between two charged particles.

We can see that the farther apart the electrons and protons are, the less the force is between them.
Lithium, boron, oxygen, and neon are all in the same row (period) of the periodic table.
The atomic radius decreases from left to right along a period due to increased effective nuclear force. From left to right the atomic number increases, indicating that more protons are added. The addition of protons increases the positive charge in the nucleus, pulling in the outer electrons by increasing the effective nuclear force, decreasing the radius.
In math terms, we can equate effective nuclear force using the force equation between two charged particles.
We can see that the farther apart the electrons and protons are, the less the force is between them.
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Which of the following would have the greatest atomic radius?
Which of the following would have the greatest atomic radius?
Atomic radius increases down each group of the periodic table and toward the left of each period. Since the elements listed are all in the same group, iodine would have the greatest atomic radius because it farther down the period compared to the others.
Atomic radius increases down each group of the periodic table and toward the left of each period. Since the elements listed are all in the same group, iodine would have the greatest atomic radius because it farther down the period compared to the others.
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Which of the following elements has the greatest atomic radius?
Which of the following elements has the greatest atomic radius?
Atomic radius can be determined using the periodic trends. Atomic radius increases to the left of a period and down a group of the periodic table. Electronegativity, in contrast, increases to the right of a period and up a group of the periodic table. Relating the two, we can see that the greater the atomic radius, the weaker its electronegativity because the electrons are farther away from the nucleus and are unable to feel the attractive force of the protons in the nucleus.
Atomic radius can be determined using the periodic trends. Atomic radius increases to the left of a period and down a group of the periodic table. Electronegativity, in contrast, increases to the right of a period and up a group of the periodic table. Relating the two, we can see that the greater the atomic radius, the weaker its electronegativity because the electrons are farther away from the nucleus and are unable to feel the attractive force of the protons in the nucleus.
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Which of the following correctly describes the trend for atomic radius in the periodic table of elements?
Which of the following correctly describes the trend for atomic radius in the periodic table of elements?
Energy level increases moving down a group of the periodic table. As energy level increases, the outer valence shell becomes more distant from the nucleus, causing atomic radius to increase.
Energy level remains constant across a period, but electrons are added within the same orbitals. When new electrons are added within the same orbital, additional protons are also added to the nucleus. This increases the effective nuclear charge, pulling the electrons closer to the nucleus. The trend for atomic radius is to decrease as we move right along a row.
This means that the general trend for atomic radius is to increase as one moves to the left and downward on the periodic table.
Energy level increases moving down a group of the periodic table. As energy level increases, the outer valence shell becomes more distant from the nucleus, causing atomic radius to increase.
Energy level remains constant across a period, but electrons are added within the same orbitals. When new electrons are added within the same orbital, additional protons are also added to the nucleus. This increases the effective nuclear charge, pulling the electrons closer to the nucleus. The trend for atomic radius is to decrease as we move right along a row.
This means that the general trend for atomic radius is to increase as one moves to the left and downward on the periodic table.
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Which of the following has the largest atomic radius?
Which of the following has the largest atomic radius?
Atomic radius increases with increasing effective nuclear charge (Z). Elements toward the right and toward the top of the periodic table have the highest Z values. Protons and electrons are added in pairs as we traverse the periodic table from left to right. A attractive force is established between the positively-charged nucleus and the negatively-charged electron cloud, which increases as the number of particles grows.
When electrons are added or taken away without the same happening to a proton, an imbalance of charge accumulates. When more electrons are present than normal, the electron cloud sags farther away from the nucleus. When fewer electrons are present than normal, the electron cloud is drawn in more tightly toward the nucleus. Atoms with extra electrons (a negative charge) will have larger nuclei than their neutral counterparts. A chloride ion will thus has a larger atomic radius than argon, a potassium ion, or a calcium ion.
Atomic radius increases with increasing effective nuclear charge (Z). Elements toward the right and toward the top of the periodic table have the highest Z values. Protons and electrons are added in pairs as we traverse the periodic table from left to right. A attractive force is established between the positively-charged nucleus and the negatively-charged electron cloud, which increases as the number of particles grows.
When electrons are added or taken away without the same happening to a proton, an imbalance of charge accumulates. When more electrons are present than normal, the electron cloud sags farther away from the nucleus. When fewer electrons are present than normal, the electron cloud is drawn in more tightly toward the nucleus. Atoms with extra electrons (a negative charge) will have larger nuclei than their neutral counterparts. A chloride ion will thus has a larger atomic radius than argon, a potassium ion, or a calcium ion.
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Which of the following alkali metals has the greatest atomic radius?
Which of the following alkali metals has the greatest atomic radius?
The trend for atomic radius is to increase going from top to bottom, as additional valence shells are added to the atom. Out of the answer choices, rubidium has the highest energy valence shell.
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With a single electron in the fifth energy level, krypton will have the highest number of energy levels of the group I elements listed.
When moving across a period, atomic radius will decrease as the number of protons increases. These protons increase the attraction between the high-energy electrons and the nucleus, effectively "shrinking" the electron cloud.
The trend for atomic radius is to increase going from top to bottom, as additional valence shells are added to the atom. Out of the answer choices, rubidium has the highest energy valence shell.
With a single electron in the fifth energy level, krypton will have the highest number of energy levels of the group I elements listed.
When moving across a period, atomic radius will decrease as the number of protons increases. These protons increase the attraction between the high-energy electrons and the nucleus, effectively "shrinking" the electron cloud.
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Which of the following atoms has the largest atomic radius?
Which of the following atoms has the largest atomic radius?
Most people clearly understand that atomic radius will increase as you go down the periodic table. However, going from left to right will actually decrease atomic radius. The reason is that the increased positive charge in the nucleus from the added protons will pull the electrons closer, decreasing the radius. Of the given options, arsenic and selenium are in the lowest row, but arsenic is more to the left. As a result, it has the largest atomic radius.
Most people clearly understand that atomic radius will increase as you go down the periodic table. However, going from left to right will actually decrease atomic radius. The reason is that the increased positive charge in the nucleus from the added protons will pull the electrons closer, decreasing the radius. Of the given options, arsenic and selenium are in the lowest row, but arsenic is more to the left. As a result, it has the largest atomic radius.
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Which atom would be expected to have the largest atomic radius?
Which atom would be expected to have the largest atomic radius?
The radius of an atom is determined by the sizes of the orbitals on its outermost shell. Below are the atomic radius trends:
1. Atomic radius increases from top to bottom within each column.
2. Atomic radius decreases from left to right within each period.
Because calcium is located closest to the bottom right on the periodic table, it has the highest atomic radius. Namely, this is due to the fact that calcium's highest energy electron is in the fourth energy shell.
The radius of an atom is determined by the sizes of the orbitals on its outermost shell. Below are the atomic radius trends:
1. Atomic radius increases from top to bottom within each column.
2. Atomic radius decreases from left to right within each period.
Because calcium is located closest to the bottom right on the periodic table, it has the highest atomic radius. Namely, this is due to the fact that calcium's highest energy electron is in the fourth energy shell.
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Which atom would be expected to have the smallest atomic radius?
Which atom would be expected to have the smallest atomic radius?
The radius of an atom is determined by the sizes of the orbitals on its outermost shell. Below are the atomic radius trends:
1. Atomic radius increases from top to bottom within each column.
2. Atomic radius decreases from left to right within a period.
Because nitrogen is furthest to the the top right on the periodic table, it has the smallest atomic radius.
The radius of an atom is determined by the sizes of the orbitals on its outermost shell. Below are the atomic radius trends:
1. Atomic radius increases from top to bottom within each column.
2. Atomic radius decreases from left to right within a period.
Because nitrogen is furthest to the the top right on the periodic table, it has the smallest atomic radius.
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Which of the following atoms has the largest atomic radius?
Which of the following atoms has the largest atomic radius?
Atomic radius increases down the periodic table and to the left. The atoms provided are all located on the same period (row). Lithium is located furthest to the left so it has the largest atomic radius. The reason for this phenomenon is that all of these atoms have their valence electrons in the n=2 energy level. However, each time we move to the right one atom, we add another electron to the valence shell and another proton in the nucleus. The more of each of these subatomic particles, the stronger the attractive force between them, thus the protons will pull the electrons closer to the nucleus, resulting in a smaller atomic radius.
Atomic radius increases down the periodic table and to the left. The atoms provided are all located on the same period (row). Lithium is located furthest to the left so it has the largest atomic radius. The reason for this phenomenon is that all of these atoms have their valence electrons in the n=2 energy level. However, each time we move to the right one atom, we add another electron to the valence shell and another proton in the nucleus. The more of each of these subatomic particles, the stronger the attractive force between them, thus the protons will pull the electrons closer to the nucleus, resulting in a smaller atomic radius.
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Which atom would be expected to have the highest atomic radius?
Which atom would be expected to have the highest atomic radius?
The radius of an atom is determined by the sizes of the orbitals on its outermost shell. Below are the
atomic radius trends:
1. Atomic radius increases from top to bottom within each column.
2. Atomic radius decreases from left to right.
All the options given are located in row 4 of the periodic table. Because titanium is located furthest to the right on the periodic table, it has the highest atomic radius.
The radius of an atom is determined by the sizes of the orbitals on its outermost shell. Below are the
atomic radius trends:
1. Atomic radius increases from top to bottom within each column.
2. Atomic radius decreases from left to right.
All the options given are located in row 4 of the periodic table. Because titanium is located furthest to the right on the periodic table, it has the highest atomic radius.
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Electronegativity is an important concept in physical chemistry, and often used to help quantify the dipole moment of polar compounds. Polar compounds are different from those compounds that are purely nonpolar or purely ionic. An example can be seen by contrasting sodium chloride, NaCl, with an organic molecule, R-C-OH. The former is purely ionic, and the latter is polar covalent.
When comparing more than one polar covalent molecule, we use the dipole moment value to help us determine relative strength of polarity. Dipole moment, however, is dependent on the electronegativity of the atoms making up the bond. Electronegativity is a property inherent to the atom in question, whereas dipole moment is a property of the bond between them.
For example, oxygen has an electronegativity of 3.44, and hydrogen of 2.20. In other words, oxygen more strongly attracts electrons when in a bond with hydrogen. This leads to the O-H bond having a dipole moment.
When all the dipole moments of polar bonds in a molecule are summed, the molecular dipole moment results, as per the following equation.
Dipole moment = charge * separation distance
Electronegativity is associated with another function, electron affinity. What is true of electron affinity?
Electronegativity is an important concept in physical chemistry, and often used to help quantify the dipole moment of polar compounds. Polar compounds are different from those compounds that are purely nonpolar or purely ionic. An example can be seen by contrasting sodium chloride, NaCl, with an organic molecule, R-C-OH. The former is purely ionic, and the latter is polar covalent.
When comparing more than one polar covalent molecule, we use the dipole moment value to help us determine relative strength of polarity. Dipole moment, however, is dependent on the electronegativity of the atoms making up the bond. Electronegativity is a property inherent to the atom in question, whereas dipole moment is a property of the bond between them.
For example, oxygen has an electronegativity of 3.44, and hydrogen of 2.20. In other words, oxygen more strongly attracts electrons when in a bond with hydrogen. This leads to the O-H bond having a dipole moment.
When all the dipole moments of polar bonds in a molecule are summed, the molecular dipole moment results, as per the following equation.
Dipole moment = charge * separation distance
Electronegativity is associated with another function, electron affinity. What is true of electron affinity?
Chlorine has a great thermodynamic desire to capture an electron, thus taking on the electronic structure of a stable noble gas. This causes chlorine to release energy when it captures an electron as it becomes more stable.
Sodium, on the other hand, would prefer to lose an electron and gain the configuration of a noble gas. Adding an electron would however award some stability to sodium, due to the complete s orbital that this would ensue.
Second electron affinity is usually encountered for such elements as oxygen and sulfur, which form anions with the addition of two electrons. The first electron affinity gives you O- or S-, and so it takes significant energy to add another electron to an already negative ion.
Chlorine has a great thermodynamic desire to capture an electron, thus taking on the electronic structure of a stable noble gas. This causes chlorine to release energy when it captures an electron as it becomes more stable.
Sodium, on the other hand, would prefer to lose an electron and gain the configuration of a noble gas. Adding an electron would however award some stability to sodium, due to the complete s orbital that this would ensue.
Second electron affinity is usually encountered for such elements as oxygen and sulfur, which form anions with the addition of two electrons. The first electron affinity gives you O- or S-, and so it takes significant energy to add another electron to an already negative ion.
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Which of the given atoms has the lowest electron affinity?
Which of the given atoms has the lowest electron affinity?
Beryllium, calcium, strontium, and radium are all alkaline earth metals in the same group of the periodic table.
The electron affinity, a measure of the energy released when an atom gains an electron (an exothermic reaction), decreases from the top of a group (column) to the bottom. The trends in electron affinity can be correlated with ionization energy. When a smaller atom gains an electron, the force between the electron and nucleus is greater than in a larger atom; thus, more energy is released when this “bond” between the nucleus and electron is formed in a smaller atom than in a larger atom, meaning that smaller atoms will have greater electron affinity. Radium is the farthest down the group of alkaline earth metals, and will have the largest atomic radius of the answer choices, giving it the lowest electron affinity.
Beryllium, calcium, strontium, and radium are all alkaline earth metals in the same group of the periodic table.
The electron affinity, a measure of the energy released when an atom gains an electron (an exothermic reaction), decreases from the top of a group (column) to the bottom. The trends in electron affinity can be correlated with ionization energy. When a smaller atom gains an electron, the force between the electron and nucleus is greater than in a larger atom; thus, more energy is released when this “bond” between the nucleus and electron is formed in a smaller atom than in a larger atom, meaning that smaller atoms will have greater electron affinity. Radium is the farthest down the group of alkaline earth metals, and will have the largest atomic radius of the answer choices, giving it the lowest electron affinity.
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Which of the given atoms has the greatest electron affinity?
Which of the given atoms has the greatest electron affinity?
Sodium, aluminum, phosphorus, and chlorine are all in the same row (period) of the periodic table.
The electron affinity, a measure of the energy released when an atom gains an electron (an exothermic reaction), increases from left to right across the periodic table because when a smaller atom gains an electron, the force between the electron and nucleus is greater than with a larger atom. More energy is released when this “bond” between the nucleus and electron is formed. Chlorine has the smallest atomic radius of the answer choices because it is located farthest to the right of the period; thus, chlorine will also have the greatest attractive force between its nucleus and electrons, giving it the highest electron affinity.
Sodium, aluminum, phosphorus, and chlorine are all in the same row (period) of the periodic table.
The electron affinity, a measure of the energy released when an atom gains an electron (an exothermic reaction), increases from left to right across the periodic table because when a smaller atom gains an electron, the force between the electron and nucleus is greater than with a larger atom. More energy is released when this “bond” between the nucleus and electron is formed. Chlorine has the smallest atomic radius of the answer choices because it is located farthest to the right of the period; thus, chlorine will also have the greatest attractive force between its nucleus and electrons, giving it the highest electron affinity.
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