1.
What is the general shape of an s orbital?
Correct Answer
A. SpHerical
Explanation
The general shape of an s orbital is spherical. This means that the electron density is evenly distributed around the nucleus, forming a symmetrical sphere. This shape is determined by the probability of finding an electron at different locations around the nucleus. In an s orbital, the probability is highest at the center and decreases as you move away from the nucleus. This spherical shape allows for maximum electron-electron repulsion, which helps to stabilize the atom.
2.
A cation
Correct Answer
C. Has a positive charge
Explanation
A cation is an ion that has a positive charge. This is because cations are formed when an atom loses one or more electrons, resulting in a net positive charge. The loss of electrons creates an imbalance between the number of protons and electrons, causing the cation to have a positive charge.
3.
According to the Heisenberg Uncertainty Principle,
Correct Answer
C. It is impossible to know both the velocity and position of an electron.
Explanation
The Heisenberg Uncertainty Principle states that it is impossible to know both the velocity and position of an electron simultaneously. This principle arises from the wave-particle duality of electrons, where they exhibit both particle-like and wave-like properties. The more accurately we try to measure the position of an electron, the less accurately we can determine its velocity, and vice versa. This principle places a fundamental limit on our ability to precisely determine the behavior and properties of subatomic particles like electrons.
4.
Which of the following atoms has the greatest ionization energy?
Correct Answer
C. Chlorine
Explanation
Chlorine has the greatest ionization energy among the given atoms. Ionization energy is the energy required to remove an electron from an atom. Chlorine has a higher ionization energy because it has a smaller atomic radius and a greater effective nuclear charge compared to the other atoms. The smaller atomic radius means that the outermost electron is closer to the nucleus, making it more strongly attracted to the positive charge of the nucleus. Additionally, the greater effective nuclear charge means that there are more protons in the nucleus, resulting in a stronger attraction between the nucleus and the electrons. Therefore, it requires more energy to remove an electron from a chlorine atom compared to the other atoms listed.
5.
Which of the following would be the LEAST stable?
Correct Answer
A. An atom of N in its excited state electron configuration
Explanation
An atom of N in its excited state electron configuration would be the least stable because when an atom is in an excited state, it has excess energy. This excess energy can cause the electron to be more easily lost or gained, making the atom more reactive and less stable compared to the other options. In contrast, an ion of Na+ has a stable electron configuration with a full outer shell, making it more stable. An atom of P in its ground state electron configuration and an atom of Ar both have full outer shells, making them more stable as well.
6.
What is the electron configuration for selenium?
Correct Answer
B. 1s22s22p63s23p64s23d104p4
Explanation
The electron configuration for selenium is 1s22s22p63s23p64s23d104p4. This configuration indicates that selenium has 34 electrons. The numbers and letters represent the different energy levels (shells) and sublevels (orbitals) that the electrons occupy. The "1s22s22p6" portion indicates the filling of the first and second energy levels, while the "3s23p64s23d104p4" portion represents the filling of the third and fourth energy levels. The superscript numbers indicate the number of electrons in each sublevel.
7.
The energy change associated with the gain of an electron is called
Correct Answer
D. Electron affinity
Explanation
Electron affinity refers to the energy change that occurs when an atom gains an electron to form a negative ion. It is a measure of the atom's ability to attract and hold onto electrons. The higher the electron affinity, the more likely an atom is to gain an electron. Ionization energy, on the other hand, is the energy required to remove an electron from an atom, while electronegativity is a measure of an atom's ability to attract electrons in a chemical bond. Electron capture is a process where an atom captures an electron from its surroundings.
8.
What is the maximum number of sublevels in the third energy level?
Correct Answer
C. 3
Explanation
The maximum number of sublevels in an energy level is determined by the principal quantum number (n) of that energy level. The formula to calculate the maximum number of sublevels is 2n^2. In this case, since it is the third energy level (n=3), the maximum number of sublevels would be 2(3^2) = 18. However, the question asks for the maximum number of sublevels specifically in the third energy level, which means we only need to consider the sublevels within that energy level. According to the Aufbau principle, the third energy level can have a maximum of 3 sublevels, which are labeled as s, p, and d. Therefore, the correct answer is 3.
9.
Which of the following atoms would have a very high electronegativity?
Correct Answer
A. Oxygen
Explanation
Oxygen would have a very high electronegativity because it is a highly electronegative element. Electronegativity is the measure of an atom's ability to attract electrons towards itself in a chemical bond. Oxygen has a high electronegativity due to its high nuclear charge and small atomic size. This means that oxygen has a strong attraction for electrons and tends to pull them towards itself when forming chemical bonds.
10.
How will an atom of magnesium obtain an octet?
Correct Answer
A. By losing two electrons
Explanation
An atom of magnesium will obtain an octet by losing two electrons. Magnesium, with an atomic number of 12, has two electrons in its outermost energy level. By losing these two electrons, magnesium will achieve a stable electron configuration, similar to that of a noble gas. This process of losing electrons is known as ionization, and it forms a positively charged ion (cation) with a full octet in the previous energy level.
11.
How many d orbitals are found in a zinc atom?
Correct Answer
A. 5
Explanation
In a zinc atom, there are a total of five d orbitals. The d orbitals are a type of atomic orbital that can hold a maximum of two electrons each. Since the d subshell can accommodate a maximum of 10 electrons, there are five d orbitals in a zinc atom. Each d orbital can hold two electrons, resulting in a total of 10 electrons in the d subshell of a zinc atom.
12.
Which of the following elements does NOT have two valence electrons?
Correct Answer
A. Lithium
Explanation
Lithium does not have two valence electrons because it is an alkali metal and belongs to the first group of the periodic table. The valence electron configuration for lithium is 2s1, meaning it has only one valence electron in its outermost energy level.
13.
Which of the following elements has the largest atomic radius?
Correct Answer
C. Strontium
Explanation
Strontium has the largest atomic radius among the given elements. Atomic radius is the distance from the nucleus to the outermost shell of an atom. As we move down a group in the periodic table, the atomic radius generally increases due to the addition of more electron shells. Strontium is located below calcium, magnesium, and beryllium in the periodic table, so it has more electron shells and a larger atomic radius compared to the other elements listed.
14.
According to Hund's Rule,
Correct Answer
D. No orbital in a sublevel may be empty if two electrons are paired in that sublevel.
Explanation
According to Hund's Rule, when electrons are added to orbitals, they are filled in order of increasing energy. This means that electrons will first fill the lowest energy orbitals before moving to higher energy ones. Additionally, Hund's Rule states that no orbital in a sublevel may be empty if two electrons are paired in that sublevel. This means that when filling orbitals with electrons, each orbital will first receive one electron before any of them can have a second electron. Therefore, the correct answer is that no orbital in a sublevel may be empty if two electrons are paired in that sublevel.
15.
How many electrons in molybdenum are found in the fourth energy level?
Correct Answer
C. 13
Explanation
The fourth energy level can hold a maximum of 32 electrons. Since molybdenum has an atomic number of 42, it has 42 electrons. To determine the number of electrons in the fourth energy level, we need to subtract the number of electrons in the first three energy levels. The first energy level can hold a maximum of 2 electrons, the second energy level can hold a maximum of 8 electrons, and the third energy level can hold a maximum of 18 electrons. Therefore, the number of electrons in the fourth energy level is 42 - 2 - 8 - 18 = 14. However, the answer options only include 6, 12, 13, and 2. Since 14 is not an option, the closest option is 13, which is the correct answer.
16.
Atoms or ions with an octet will be
Correct Answer
D. Stable.
Explanation
Atoms or ions with an octet are stable because they have achieved a full outer electron shell, which is the most stable configuration. This stability is achieved by gaining or losing electrons to reach a total of 8 electrons in the outer shell, similar to the electron configuration of noble gases. Stable atoms or ions are less likely to undergo chemical reactions and are more likely to exist in their current form without undergoing significant changes.
17.
An atom of silicon will have how many valence electrons?
Correct Answer
D. 4
Explanation
An atom of silicon has 14 electrons in total. To determine the number of valence electrons, we look at the outermost energy level, which is the third energy level in the case of silicon. The third energy level can hold a maximum of 8 electrons, but silicon only has 4 electrons in its outermost energy level. Therefore, silicon has 4 valence electrons.
18.
Which of the following atoms has an octet?
Correct Answer
B. Argon
Explanation
Argon has an octet because it is a noble gas and has a full outer electron shell. Noble gases have stable electron configurations and do not readily form bonds with other atoms. In the case of argon, it has a total of 18 electrons, with 8 of them in the outermost shell. This satisfies the octet rule, which states that atoms tend to gain, lose, or share electrons in order to achieve a stable configuration with 8 electrons in the outer shell. Therefore, argon is the only atom listed that has an octet.
19.
Which of the following elements has six valence electrons?
Correct Answer
C. Te
Explanation
The element with six valence electrons is Te (tellurium). Valence electrons are the electrons in the outermost energy level of an atom, and they determine the chemical properties of an element. In the case of Te, it is located in group 16 of the periodic table, also known as the oxygen family. Elements in this group typically have six valence electrons. Therefore, Te has six valence electrons.
20.
Which of the following atoms would have the LOWEST ionization energy?
Correct Answer
A. Lithium
Explanation
Lithium would have the lowest ionization energy because it is the furthest left and closest to the noble gases in the periodic table. As you move from left to right across a period, the ionization energy generally increases because the atomic radius decreases and the electrons are held more tightly. Since lithium is at the beginning of the period, it has a larger atomic radius and the electrons are not held as tightly, making it easier to remove an electron and therefore having the lowest ionization energy among the given atoms.
21.
How many electrons are found in the third energy level of calcium?
Correct Answer
C. 8
Explanation
The third energy level of calcium can hold a maximum of 8 electrons. This is because the first energy level can hold a maximum of 2 electrons, the second energy level can hold a maximum of 8 electrons, and the third energy level can also hold a maximum of 8 electrons. Since calcium has 20 electrons in total, 2 of them will be in the first energy level, 8 will be in the second energy level, and the remaining 8 will be in the third energy level. Therefore, the correct answer is 8.
22.
What is the electron configuration for scandium?
Correct Answer
B. 1s22s22p63s23p64s23d1
Explanation
The electron configuration for scandium is 1s22s22p63s23p64s23d1. This configuration follows the Aufbau principle, which states that electrons fill the lowest energy levels first before moving to higher energy levels. Scandium has 21 electrons, so the first 20 electrons fill up the 1s, 2s, 2p, 3s, and 3p orbitals. The remaining electron goes into the 4s orbital before filling the 3d orbital.
23.
Elements that have seven valence electrons are
Correct Answer
B. Halogens.
Explanation
Halogens are the elements that have seven valence electrons. Valence electrons are the electrons in the outermost energy level of an atom, and halogens have seven electrons in their outermost energy level. This makes them highly reactive and likely to form compounds with other elements. Metals, noble gases, and elements in Group 7 of the Periodic Table do not necessarily have seven valence electrons.
24.
Fluorine has a very high
Correct Answer
D. Electronegativity.
Explanation
The correct answer is electronegativity. Fluorine has a very high electronegativity, which means it has a strong ability to attract electrons towards itself in a chemical bond. This is due to its small atomic size and high nuclear charge. Fluorine's electronegativity is the highest among all the elements on the periodic table, making it the most electronegative element.
25.
What is the symbol for the gallium ion?
Correct Answer
C. Ga3+
Explanation
The symbol for the gallium ion is Ga3+. The number 3+ indicates that the gallium ion has a positive charge of 3. This means that the ion has lost three electrons, resulting in a positive charge.
26.
Atoms are most stable when they have
Correct Answer
B. Eight valence electrons.
Explanation
Atoms are most stable when they have eight valence electrons. This is because having eight valence electrons, also known as a full outer shell, satisfies the octet rule. The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable electron configuration similar to that of the noble gases. By having a full outer shell, atoms achieve a lower energy state and increased stability, making eight valence electrons the most favorable configuration.
27.
An atom of gallium has how many electrons in its fifth energy level?
Correct Answer
D. 0
Explanation
The fifth energy level of an atom can hold a maximum of 50 electrons. However, the atom of gallium has only 31 electrons, so it does not have any electrons in its fifth energy level. Therefore, the correct answer is 0.
28.
Which of the following atoms is the largest?
Correct Answer
A. Potassium
Explanation
Potassium is the largest atom among the given options. This is because as you move down a group in the periodic table, the atomic size increases. Potassium is located below sodium and magnesium in the same group, so it has more energy levels and a larger atomic radius. Krypton, on the other hand, is a noble gas and is located in a different period, so it is smaller than all the other options.
29.
What is the electron configuration for chlorine?
Correct Answer
A. 1s22s22p63s23p5
Explanation
The electron configuration for chlorine is 1s22s22p63s23p5. This means that chlorine has 17 electrons. The first energy level (n=1) has 2 electrons in the 1s sublevel. The second energy level (n=2) has 8 electrons, with 2 in the 2s sublevel and 6 in the 2p sublevel. The third energy level (n=3) has 7 electrons, with 2 in the 3s sublevel and 5 in the 3p sublevel. Therefore, the electron configuration for chlorine is 1s22s22p63s23p5.
30.
An atom of sulfur has how many valence electrons?
Correct Answer
C. 6
Explanation
An atom of sulfur has 6 valence electrons. Valence electrons are the electrons in the outermost energy level of an atom, and they are responsible for the chemical behavior of the atom. Sulfur is in Group 16 of the periodic table, which means it has 6 valence electrons.
31.
How many unpaired electrons are found in an atom of sulfur?
Correct Answer
C. 2
Explanation
An atom of sulfur has 16 electrons. To determine the number of unpaired electrons, we need to look at the electron configuration. The electron configuration of sulfur is 1s2 2s2 2p6 3s2 3p4. In the outermost energy level (3p), there are four electrons. Two of these electrons will pair up in one of the 3p orbitals, while the other two electrons will remain unpaired in separate 3p orbitals. Therefore, there are 2 unpaired electrons in an atom of sulfur.
32.
The iodine ion will have the symbol
Correct Answer
D. I-
Explanation
The iodine ion will have the symbol I- because it has gained one electron, resulting in a negative charge. The symbol "I" represents the element iodine, and the negative charge is indicated by the superscript "-".
33.
An atom of sodium will generally tend to
Correct Answer
A. Lose one electron.
Explanation
Sodium is an alkali metal located in Group 1 of the periodic table. It has one valence electron in its outermost energy level. In order to achieve a stable electron configuration, sodium tends to lose this one electron and form a positive ion with a full outer energy level. This is because it is energetically favorable for sodium to have a complete octet, similar to the noble gas configuration of neon. Therefore, the correct answer is that sodium will generally tend to lose one electron.
34.
An atom of iron has how many electrons in its 3d sublevel?
Correct Answer
D. 6
Explanation
The atomic number of iron is 26, which means it has 26 electrons. The 3d sublevel can hold a maximum of 10 electrons. Therefore, an atom of iron will have 6 electrons in its 3d sublevel.
35.
Which of the following is a ground state electron configuration for a transition metal?
Correct Answer
A. 1s22s22p63s23p64s23d10
Explanation
The correct answer is 1s22s22p63s23p64s23d10. This electron configuration represents a ground state electron configuration for a transition metal because it follows the Aufbau principle and Hund's rule. The Aufbau principle states that electrons will fill the lowest energy levels first, so the 1s, 2s, 2p, and 3s orbitals are filled before the 3p and 4s orbitals. Hund's rule states that when orbitals of equal energy are available, electrons will occupy separate orbitals before pairing up. In this electron configuration, the 3d orbital is half-filled with 5 electrons, following Hund's rule, and the 4s orbital is filled with 2 electrons.
36.
When is a burst of light emitted?
Correct Answer
B. When an electron moves from an excited state to the ground state
Explanation
When an electron moves from an excited state to the ground state, a burst of light is emitted. This is because when an electron is in an excited state, it has absorbed energy and is in a higher energy level. As the electron moves back to its ground state, it releases the excess energy in the form of light. This phenomenon is known as emission of light and is commonly observed in various light sources such as fluorescent bulbs and lasers.
37.
Anions are always
Correct Answer
C. Negatively charged.
Explanation
Anions are negatively charged ions because they have gained one or more electrons, resulting in an excess of negative charge. This is in contrast to cations, which are positively charged ions that have lost one or more electrons. The negative charge of anions allows them to interact with positively charged species, forming ionic compounds through electrostatic attractions.
38.
How many p sublevels are found in a vanadium atom?
Correct Answer
B. 2
Explanation
The correct answer is 2 because the p sublevel can hold a maximum of 6 electrons, and vanadium has an atomic number of 23. The electron configuration of vanadium is 1s2 2s2 2p6 3s2 3p6 4s2 3d3, indicating that it has 2 p sublevels.
39.
What is the general shape of a p orbital?
Correct Answer
D. Figure-eight
Explanation
A p orbital has a figure-eight shape. This shape is formed by two lobes that are separated by a node, which is a region of zero electron density. The lobes are symmetrical and extend along the three Cartesian axes. The figure-eight shape allows the p orbital to accommodate two electrons with opposite spins. This shape is characteristic of p orbitals and is different from the spherical shape of s orbitals.
40.
Which of the following is the ground state electron configuration for chromium?
Correct Answer
D. 1s22s22p63s23p64s13d5
Explanation
The ground state electron configuration for chromium is 1s22s22p63s23p64s13d5. This is because chromium has an atomic number of 24, which means it has 24 electrons. When we fill up the orbitals according to the Aufbau principle, we start with the lowest energy level and fill up each orbital before moving to the next one. The electron configuration for chromium follows this pattern, filling up the 1s, 2s, 2p, 3s, 3p, 4s, and 3d orbitals. Therefore, the correct answer is 1s22s22p63s23p64s13d5.
41.
Which of these elements has the greatest atomic radius?
Correct Answer
C. Xe
Explanation
Xe has the greatest atomic radius among the given elements. Atomic radius refers to the size of an atom, and it generally increases as you move down a group in the periodic table. Xe is located at the bottom of the noble gases group (Group 18), while Ar, Ne, and He are located above it. Therefore, Xe has more electron shells and a larger atomic radius compared to the other elements.
42.
Phosphorus obtains an octet by
Correct Answer
B. Gaining three electrons.
Explanation
Phosphorus obtains an octet by gaining three electrons. This is because phosphorus has five valence electrons and needs a total of eight electrons to achieve a stable octet configuration. By gaining three electrons, phosphorus can fill its outermost energy level and achieve a stable electron configuration, similar to the nearest noble gas, argon.
43.
Which of the following statements is true?
Correct Answer
A. Iodine has more energy levels that chlorine; therefore, iodine is larger.
Explanation
Iodine has more energy levels than chlorine, which means it has more electron shells. As the number of energy levels increases, the size of the atom also increases. This is because each energy level is further away from the nucleus, resulting in a larger atomic radius. Therefore, the statement is true and iodine is indeed larger than chlorine.
44.
Which of the following is the ground state electron configuration for a noble gas?
Correct Answer
C. 1s22s22p63s23p64s23d104p6
Explanation
The ground state electron configuration for a noble gas is characterized by a completely filled outermost electron shell. In this case, the electron configuration 1s22s22p63s23p64s23d104p6 represents a noble gas because it has a complete set of electrons in its outermost shell.
45.
How many energy levels can be found in an atom of silver?
Correct Answer
B. 5
Explanation
An atom of silver can have 5 energy levels. Energy levels in an atom represent the different possible energy states that an electron can occupy. In the case of silver, there are 5 possible energy levels for its electrons to occupy. Each energy level can hold a certain number of electrons, with the innermost level holding the least and the outermost level holding the most. Therefore, the correct answer is 5.