1.
How many electrons are shared in a covalent bond
Correct Answer
B. 2
Explanation
In a covalent bond, two electrons are shared between two atoms. This sharing of electrons creates a strong bond between the atoms, allowing them to form a stable molecule. The shared electrons are attracted to both nuclei, creating a balanced distribution of charge and resulting in a stable arrangement. Therefore, the correct answer is 2.
2.
Electronegativity is defined as an atom's ability to do what?
Correct Answer
D. Attract electrons
Explanation
Electronegativity is a measure of an atom's ability to attract electrons towards itself when it is part of a chemical bond. It indicates the strength of an atom's pull on shared electrons in a covalent bond. The higher the electronegativity of an atom, the more strongly it attracts electrons. Therefore, the correct answer is "attract electrons."
3.
Purely ionic means that
Correct Answer
A. An atom completely gives up its valence electrons to another atom
4.
Bond energy is the energy required to
Correct Answer
D. Break a chemical bond
Explanation
Bond energy is the amount of energy needed to break a chemical bond. When a bond is broken, energy is required to overcome the attractive forces between the atoms. Breaking a chemical bond involves the separation of atoms and the breaking of the bond's shared electrons. Therefore, the correct answer is "break a chemical bond".
5.
Choose the compound with the greatest bond energy according to its length.
Correct Answer
A. 45pm
Explanation
The compound with the greatest bond energy according to its length is 45pm. Bond energy is the energy required to break a chemical bond, and typically shorter bond lengths indicate stronger bonds. Therefore, the compound with a bond length of 45pm would have the highest bond energy compared to the other options provided.
6.
Boron, does not follow the octet rule. How many electrons satisfies its outer shell, instead of it being 8.
Correct Answer
D. 6
Explanation
Boron, with atomic number 5, has 5 electrons in its outer shell. It does not follow 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 their outer shell. Instead, boron satisfies its outer shell by sharing 3 electrons with other atoms, resulting in a total of 6 electrons in its outer shell.
7.
How do we know what the central atom for either a resonance or lewis structure is?
Correct Answer
B. The atom that has only one of it, in the molecule, is the central atom
Explanation
The correct answer is that the central atom is the one that has only one of it in the molecule. This is because in most cases, the central atom is the one that forms the fewest bonds with other atoms. This allows the other atoms to maximize their bonding and achieve a stable electron configuration. Additionally, the central atom is usually the one that is less electronegative, as it is more likely to share its electrons with other atoms.
8.
Give an example of a salt that is held together by ionic bonds
Correct Answer
D. NaCl
Explanation
NaCl is an example of a salt that is held together by ionic bonds. Ionic bonds form between a metal cation (in this case, Na+) and a non-metal anion (Cl-). In NaCl, sodium loses an electron to become a positively charged ion, while chlorine gains that electron to become a negatively charged ion. The opposite charges attract each other, resulting in the formation of an ionic bond between the two ions. This bond is strong and requires a significant amount of energy to break.
9.
I have a lower melting point than ionic compounds. What am i?
Correct Answer
C. Solid molecular compound
Explanation
The given answer, "Solid molecular compound," is correct because molecular compounds generally have lower melting points than ionic compounds. This is because molecular compounds are made up of covalent bonds, which are weaker than the electrostatic forces present in ionic compounds. Therefore, it requires less energy to break the intermolecular forces in molecular compounds, resulting in a lower melting point.
10.
What best decribes this type of compound: Hard, brittle, not electrical conductors as solids
Correct Answer
A. Ionic
Explanation
Ionic compounds are composed of ions held together by electrostatic forces of attraction. These compounds typically have high melting and boiling points, are hard and brittle, and do not conduct electricity as solids. Therefore, the given properties of being hard, brittle, and not electrical conductors as solids align with the characteristics of ionic compounds.
11.
Polyatomic ions are what?
Correct Answer
B. Charged group of covalently bonded atoms
Explanation
Polyatomic ions are a type of ion that consists of a charged group of covalently bonded atoms. These ions are formed when atoms share electrons to achieve a stable electron configuration. Unlike individual atoms, polyatomic ions have an overall charge due to the unequal distribution of electrons within the group. This charge allows them to interact with other ions and molecules in chemical reactions.
12.
What are the electrons doing in the sea of electrons?
Correct Answer
D. Moving freely throughout the network of metal atoms
Explanation
The correct answer is "Moving freely throughout the network of metal atoms." In a metal, the outermost electrons are not tightly bound to individual atoms but instead form a "sea" or cloud of electrons that are delocalized and can move freely throughout the metal lattice. This allows metals to conduct electricity and heat effectively.
13.
When you think of the vacant orbitals in the atoms energy levels within metallic bonding, this term comes to mind
Correct Answer
B. Overlapping
Explanation
In metallic bonding, vacant orbitals in the atom's energy levels overlap with each other. This overlapping allows for the delocalization of electrons, leading to the formation of a metallic bond. Therefore, the term "overlapping" is the most appropriate in this context.
14.
What is not a characteristic of metallic bonding?
Correct Answer
A. Brittleness
Explanation
Brittleness is not a characteristic of metallic bonding. Metallic bonding is a type of chemical bonding that occurs between metal atoms, where the valence electrons are delocalized and free to move throughout the metal lattice. This gives metals their unique properties such as electrical conductivity, ductility, and malleability. However, brittleness is a characteristic of other types of bonding, such as ionic or covalent bonding, where the arrangement of atoms is more rigid and less flexible.
15.
In metallic bonding,
Correct Answer
C. One plane of atoms can easily slide past another plane without breaking bonds
Explanation
In metallic bonding, one plane of atoms can easily slide past another plane without breaking bonds. This is because metallic bonding involves the delocalization of electrons, creating a "sea of electrons" that is shared among all the atoms in the metal. These delocalized electrons are not confined to a specific bond, allowing the planes of atoms to slide past each other without breaking the metallic bonds. This property gives metals their characteristic malleability and ductility.
16.
VSEPR theory is not limited to what?
Correct Answer
D. All of the above
Explanation
The VSEPR theory is not limited to any specific type of molecule. It can be applied to both small and large molecules, as well as polar and nonpolar molecules. The theory is a useful tool for predicting the shapes and geometries of molecules based on the repulsion between electron pairs. Therefore, the correct answer is "All of the above" because the VSEPR theory can be applied to all types of molecules.
17.
If you only have two atoms, are you able to come up with the shape?
Correct Answer
A. Yes
Explanation
Yes, it is possible to determine the shape with only two atoms. The shape of a molecule is determined by the arrangement of atoms and the type of bonds between them. In the case of two atoms, they can only form a single bond, resulting in a linear shape. Therefore, the shape can be determined without knowing the specific atoms or the number of atoms being bonded.
18.
Water is an example of a :
Correct Answer
D. Polar molecule
Explanation
Water is an example of a polar molecule because it has a bent molecular shape and an unequal distribution of charge. The oxygen atom in water is more electronegative than the hydrogen atoms, causing the oxygen to pull the shared electrons closer to itself. This creates a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. The unequal distribution of charge gives water a positive and negative end, making it a polar molecule.
19.
In the ABE designation, one E stands for what?
Correct Answer
C. One unshared electron pair
Explanation
The ABE designation is used to describe the shape of a molecule in the VSEPR theory. The "E" in ABE stands for electron pairs that are not involved in bonding with the central atom. These unshared electron pairs are also known as lone pairs and they influence the shape of the molecule. Therefore, the correct answer is "one unshared electron pair".
20.
How many valence electrons should be shown around a F atom if it is bonded to one other atom?
Correct Answer
B. 6
Explanation
When a fluorine (F) atom is bonded to one other atom, it forms a single covalent bond. Each covalent bond involves the sharing of two electrons. Since fluorine has 7 valence electrons, it needs to gain one more electron to achieve a stable octet. Thus, when bonded to one other atom, a fluorine atom should show 6 valence electrons.
21.
How many 2p orbitals does oxygen have?
Correct Answer
B. 3
Explanation
Oxygen has three 2p orbitals. In the electron configuration of oxygen (1s² 2s² 2p⁴), there are two electrons in the 2p sublevel. Each 2p orbital can hold a maximum of two electrons, so there are three 2p orbitals in total.
22.
If two atoms have similar electronegativities, what can we predict about the type of bond that will form between them?
Correct Answer
A. Non polar covalent
Explanation
When two atoms have similar electronegativities, it indicates that they have similar abilities to attract electrons. In such a case, a non polar covalent bond is likely to form between them. In a non polar covalent bond, the atoms share the electrons equally, resulting in a balanced distribution of charge. This type of bond occurs when there is no significant difference in electronegativity between the atoms involved.
23.
Hydrogen can sometimes form double bonds
Correct Answer
B. False
Explanation
Hydrogen cannot form double bonds because it only has one electron to share. Double bonds require two pairs of electrons to be shared between two atoms. Therefore, the statement that hydrogen can sometimes form double bonds is false.
24.
Hydrogen will never be the center atom (bonded to two or more other atoms)
Correct Answer
A. True
Explanation
The explanation for the given correct answer is that hydrogen has only one electron and can only form one bond. Therefore, it cannot be the center atom in a molecule where it is bonded to two or more other atoms. This is because the center atom in a molecule is typically the one that forms multiple bonds with other atoms.
25.
Hydrogen is an exception to the octet rule, for example any hydrogen that is already bonded to another atom, has no extra lone pairs around it.
Correct Answer
A. True
Explanation
Hydrogen is an exception to the octet rule because it can only form one bond, unlike other elements that can form multiple bonds. Therefore, when hydrogen is already bonded to another atom, it does not have any extra lone pairs around it. This is because hydrogen only needs two electrons to achieve a stable electron configuration, rather than the eight electrons required by the octet rule. Hence, the statement is true.
26.
How many extra electrons does this atom need in order to fill the octet rule?1s2 2s2 2p4
Correct Answer
2
Explanation
The electron configuration of the atom given is 1s2 2s2 2p4. The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable configuration with eight valence electrons. In this case, the atom already has six valence electrons (2 in the 2s orbital and 4 in the 2p orbital), so it needs two more electrons to fill its outermost energy level and satisfy the octet rule. Therefore, the correct answer is 2.
27.
How many extra electrons does this atom need in order to fill the octet rule?1s2 2s2 2p5
Correct Answer
1
Explanation
The given electron configuration is for a nitrogen atom. Nitrogen has 5 valence electrons, and in order to fill the octet rule (having 8 valence electrons), it needs 3 more electrons. Therefore, the atom needs 3 extra electrons, not 1.
28.
How many extra electrons does this atom need in order to fill the octet rule?1s2 2s2 2p1
Correct Answer
B. 5
Explanation
The given electron configuration of the atom is 1s2 2s2 2p1, which indicates that there are a total of 5 valence electrons. The octet rule states that atoms tend to gain, lose, or share electrons to achieve a stable electron configuration with 8 electrons in the outermost energy level. Since this atom only has 5 valence electrons, it needs 3 more electrons to fill its outermost energy level and satisfy the octet rule. Therefore, the atom needs 5 extra electrons.
29.
Out of the following intermolecular forces, choose the strongest.
Correct Answer
B. Dipole-Dipole
Explanation
Dipole-dipole forces are the strongest intermolecular forces among the given options. These forces occur between polar molecules, where the positive end of one molecule attracts the negative end of another molecule. This attraction is stronger than the other forces mentioned. Hybrid orbital forces are not a recognized intermolecular force, while London dispersion forces are weaker than dipole-dipole forces. Lattice forces refer to the forces holding together a crystalline lattice structure, which are typically stronger than intermolecular forces.
30.
If you were to draw SiF4, which atom would be the centrer atom?
Correct Answer
D. Si
Explanation
SiF4 is a molecule composed of one silicon atom (Si) and four fluorine atoms (F). In order to determine the central atom, we need to consider the concept of electronegativity. Fluorine is the most electronegative element, meaning it has a strong attraction for electrons. Since Si is less electronegative than F, it is more likely to be the central atom. Additionally, Si is capable of forming more bonds compared to F, making it a suitable choice for the central atom in SiF4.
31.
A polar molecule contains no bonds
Correct Answer
B. False
Explanation
A polar molecule actually does contain bonds. In a polar molecule, the electrons are not evenly distributed, resulting in a partial positive charge on one end and a partial negative charge on the other. This uneven distribution of charge is caused by differences in electronegativity between the atoms involved in the bond. Hence, a polar molecule does have bonds.
32.
C,O, and N all are capable of what?
Correct Answer
D. Forming multiple bonds
Explanation
C, O, and N are all elements that have the ability to form multiple bonds. This means that they can share more than one pair of electrons with other atoms in order to achieve a stable electron configuration. This property allows these elements to form a wide range of compounds with different structures and properties.