1.
What is the charge of the anion: CO3 ?
Correct Answer
B. 2-
Explanation
The charge of the anion CO3 is 2-. This is because the CO3 ion is a polyatomic ion called carbonate, which consists of one carbon atom bonded to three oxygen atoms. Carbon has a valence of 4, and oxygen has a valence of 2. In order for the compound to be electrically neutral, the total charge of the carbonate ion must be -2. Therefore, the charge of the anion CO3 is 2-.
2.
Determine the correct chemical name for: Fe(NO3)2
Correct Answer
D. Iron (II) Nitrate
Explanation
The correct chemical name for Fe(NO3)2 is Iron (II) Nitrate. In this compound, Fe represents iron with a +2 oxidation state, and NO3 represents the nitrate ion. The Roman numeral II in parentheses indicates the oxidation state of iron, which is necessary to specify in this compound as iron can have multiple oxidation states. Nitrate is the correct anion for this compound, as it consists of one nitrogen atom and three oxygen atoms. Therefore, the correct name is Iron (II) Nitrate.
3.
Determine the correct chemical formula for: Sodium Phosphate
Correct Answer
E. Na3PO4
Explanation
The correct chemical formula for Sodium Phosphate is Na3PO4. This is because the formula indicates that there are three sodium (Na) atoms, one phosphorus (P) atom, and four oxygen (O) atoms in the compound. The subscript numbers indicate the number of each element present in the formula.
4.
What is the same between Manganese (II) Chloride and Manganese (IV) Chloride?
Correct Answer
D. 2 of the above
Explanation
The correct answer is "2 of the above". Manganese (II) Chloride and Manganese (IV) Chloride have the same charge of Manganese and the charge of Chlorine. However, the overall charge may not be the same for both compounds.
5.
Determine the number of copper in one molecule of: Copper (I) Sulfate
Correct Answer
C. 2
Explanation
Copper (I) sulfate contains one copper atom in its chemical formula, CuSO4. The Roman numeral (I) indicates that copper has a +1 oxidation state in this compound. Since the sulfate ion (SO4) has a charge of -2, the copper ion must have a charge of +2 to balance the overall charge of the compound. Therefore, there are two copper atoms in one molecule of copper (I) sulfate.
6.
Which of the following is the correct electron configuration for Carbon?
Correct Answer
C. 1s^2 2s^2 2p^2
Explanation
The correct electron configuration for Carbon is 1s^2 2s^2 2p^2. This configuration represents the distribution of electrons in the energy levels and orbitals of the carbon atom. The first energy level (n=1) has 2 electrons in the 1s orbital. The second energy level (n=2) has 2 electrons in the 2s orbital and 2 electrons in the 2p orbital. This configuration satisfies the octet rule, which states that atoms tend to gain, lose, or share electrons in order to achieve a full outer shell of 8 electrons.
7.
The maximum number of electrons in the 3d subshell is:
Correct Answer
C. 10
Explanation
The maximum number of electrons in the 3d subshell is 10 because each orbital can hold a maximum of 2 electrons and there are 5 orbitals in the 3d subshell. Therefore, 5 orbitals x 2 electrons per orbital = 10 electrons.
8.
Elements with 1-9 electrons in their 4d subshell are located:
Correct Answer
D. Period 5 Transition metals
Explanation
Elements with 1-9 electrons in their 4d subshell are located in the Period 5 Transition metals. This is because the 4d subshell is filled in the fifth period of the periodic table, which corresponds to the transition metals. The transition metals are known for their ability to form multiple oxidation states and their characteristic properties, such as high melting and boiling points, conductivity, and catalytic activity. Therefore, the correct answer is Period 5 Transition metals.
9.
Elements with 5 electrons on their outermost p shell are located:
Correct Answer
B. Halogens
Explanation
Halogens are located in Group 17 of the periodic table and have 5 electrons on their outermost p shell. They include elements such as fluorine, chlorine, bromine, iodine, and astatine. These elements have a strong tendency to gain one electron to achieve a stable octet configuration, making them highly reactive nonmetals. Therefore, the correct answer is Halogens.
10.
The electron configuration: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^6 corresponds to the element:
Correct Answer
A. Iron, Fe
Explanation
The correct answer is Iron, Fe. The given electron configuration matches the electron configuration of Iron. The electron configuration represents the arrangement of electrons in an atom's electron shells. In this case, the electron configuration shows that Iron has 26 electrons. The numbers and letters in the electron configuration represent the energy levels and subshells that the electrons occupy. The correct electron configuration for Iron is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2, with a total of 26 electrons.
11.
The maximum number of electrons in the f subshell would correspond with:
Correct Answer
B. The number of elements in the lanthanoids and actinoids
Explanation
The f subshell can hold a maximum of 14 electrons. The lanthanoids and actinoids, also known as the f-block elements, occupy the f subshell. Therefore, the maximum number of electrons in the f subshell would correspond with the number of elements in the lanthanoids and actinoids.
12.
Which bonding model best describes: CH4 (g) ? (Note: CH4 is a gas)
Correct Answer
D. Molecular Covalent
Explanation
The bonding model that best describes CH4 (g) is molecular covalent. In this model, the carbon atom shares its four valence electrons with the four hydrogen atoms, forming four covalent bonds. This results in a stable molecule where the electrons are shared between the atoms rather than transferred. Since CH4 is a gas, it indicates weak intermolecular forces between the molecules, further supporting the molecular covalent model.
13.
Which bonding model best describes: SiO2 (s) ? (Note: SiO2 (s) is very hard)
Correct Answer
B. Network Covalent
Explanation
SiO2 (s) is best described by the network covalent bonding model. In this model, the atoms are bonded together by a network of covalent bonds, forming a three-dimensional structure. SiO2 is composed of silicon and oxygen atoms, and each silicon atom is bonded to four oxygen atoms through strong covalent bonds. This results in a rigid and highly organized structure, which gives SiO2 its hardness. The network covalent bonding model explains the strong and stable nature of SiO2.
14.
Which of the following is NOT a property of Ionic substances?
Correct Answer
B. They conduct electricity when dry
Explanation
Ionic substances are made up of cations and anions, they conduct electricity when dissolved in water, and they dissolve in water. However, they do not conduct electricity when they are dry. This is because in their solid state, the ions are held tightly in a fixed position and cannot move to carry an electric charge. It is only when they are dissolved in water or molten that the ions are free to move and conduct electricity.
15.
Which of the following is NOT a property of Metallic substances?
Correct Answer
A. Dissolves in water
Explanation
Metallic substances do not dissolve in water. This is because metallic substances have a strong metallic bond, which is a type of chemical bond that involves the sharing of electrons between metal atoms. This bond is very strong and stable, making it difficult for metallic substances to break apart and dissolve in water. Therefore, the property of dissolving in water does not apply to metallic substances.
16.
Which of the following is NOT a property of Molecular Covalent substances?
Correct Answer
B. They always dissolve in water
Explanation
Molecular covalent substances do not always dissolve in water. This is because the intermolecular forces between the molecules of these substances are not strong enough to break the hydrogen bonds between water molecules. Therefore, they may or may not dissolve in water depending on the specific molecular structure and polarity of the substance.
17.
Which of the following is NOT a property of Network Covalent substances?
Correct Answer
E. None of the above
Explanation
Network covalent substances are characterized by the presence of a three-dimensional network of covalent bonds. They do not dissolve because the strong covalent bonds between their atoms make it difficult for them to separate and mix with a solvent. They do not conduct electricity because the electrons in their covalent bonds are localized and not free to move. They are extremely hard due to the strong covalent bonds throughout the network. Finally, they are made up of non-metal and metalloid atoms, which have the ability to form covalent bonds. Therefore, all the given properties are indeed properties of network covalent substances.
18.
Predict the bonding model for KI, potassium iodine
Correct Answer
A. Ionic
Explanation
The correct answer is ionic because KI consists of a metal (potassium) and a non-metal (iodine), which typically form ionic compounds. In an ionic bond, the metal atom loses electrons to become a cation, while the non-metal atom gains electrons to become an anion. The resulting oppositely charged ions are held together by electrostatic forces, forming an ionic compound.
19.
CO2 (Carbon dioxide) is molecular covalent. Which piece of evidence best supports this?
Correct Answer
C. It is a gas at room temperature
Explanation
The fact that carbon dioxide is a gas at room temperature supports the idea that it is a molecular covalent compound. In general, covalent compounds tend to have low melting and boiling points, which allows them to exist as gases or liquids at room temperature.
20.
Diamond (C) is a very hard substance. Which bonding model best describes it?
Correct Answer
D. Network Covalent
Explanation
Diamond is a very hard substance because it is made up of a network of covalent bonds. In a network covalent bonding model, atoms are bonded together in a three-dimensional network structure, where each atom is covalently bonded to its neighboring atoms. This results in a strong and rigid structure, which gives diamond its hardness. Ionic bonding involves the transfer of electrons between atoms, molecular covalent bonding involves the sharing of electrons between atoms in discrete molecules, and metallic bonding involves the delocalization of electrons in a sea of positive ions. Structural covalent is not a recognized bonding model.