CHEM 3300 BWT1 Inorganic Chemistry

Explanation:

Transition metals are defined as elements with partially filled d orbitals. In their electron configurations, the electrons with the highest energy are in the d sublevel, not the s or f orbitals. The s orbital of the outermost shell is often filled first, but the d electrons are responsible for the characteristic chemistry of transition metals, including variable oxidation states and colored compounds.

Correct Answer:

The electrons with the highest energy are in a d sublevel

Why Other Options Are Wrong:

The highest occupied s and p sublevels are completely filled. This is incorrect because s may be filled, but p orbitals are not typically involved in the highest energy electrons for transition metals.

The highest occupied s and p sublevels are partially filled. This is false; the d sublevel defines transition metals, and s may be filled, but p is not the main contributor.

The electrons with the highest energy are in the f sublevel. This is incorrect; f sublevels are characteristic of inner transition elements (lanthanides and actinides), not transition metals.

Explanation:

The formal charge of an atom is calculated to determine the distribution of electrons within a molecule relative to the neutral atom. The correct formula is Formal Charge = Valence Electrons - (Non-bonding Electrons + 1/2 Bonding Electrons). This formula accounts for electrons that an atom “owns” in a molecule: non-bonding electrons are fully assigned to the atom, and bonding electrons are split equally between the two bonded atoms. The other options are incorrect because they either misrepresent the subtraction or addition of electrons, or incorrectly distribute bonding electrons.

Correct Answer:

Formal Charge = Valence Electrons - (Non-bonding Electrons + 1/2 Bonding Electrons)

Why Other Options Are Wrong:

Formal Charge = Valence Electrons - Lone Pair Electrons - 1/2(Bonding Electrons). This is almost correct in concept, but the formula is usually written as the sum of non-bonding electrons plus half the bonding electrons subtracted from valence electrons; writing it as two separate subtractions is unconventional and can lead to calculation errors.

Formal Charge = Lone Pair Electrons + 1/2 Bonding Electrons - Valence Electrons. This is incorrect because it reverses the sign; the valence electrons should be the starting point from which assigned electrons are subtracted.

Formal Charge = Valence Electrons + Lone Pair Electrons - 1/2(Bonding Electrons). This is wrong because non-bonding electrons should be subtracted, not added, in calculating formal charge.

Explanation:

A redox reaction is defined as a chemical reaction in which there is a simultaneous oxidation and reduction process. Oxidation involves the loss of electrons or an increase in oxidation state, while reduction involves the gain of electrons or a decrease in oxidation state. In any redox reaction, the total increase in oxidation state for the oxidized species must be balanced by a corresponding decrease in oxidation state for the reduced species. Therefore, the statement that in a redox reaction any increase in the oxidation state of a reactant must be accompanied by a decrease in the oxidation state of another reactant accurately reflects the fundamental principle of electron conservation in redox chemistry.

Correct Answer:

In a redox reaction, any increase in the oxidation state of a reactant must be accompanied by a decrease in the oxidation state of another reactant

Why Other Options Are Wrong:

A redox reaction involves wither the transfer of an electron or a change in the oxidation state of an element. This is partially correct but imprecise because redox reactions inherently involve both oxidation and reduction; it is not sufficient to consider only a transfer or a change in oxidation state without the complementary process.

If any of the reactants or products in a reaction contain oxygen, the reaction is a redox reaction. This is incorrect because the presence of oxygen alone does not define a redox reaction. Many reactions involving oxygen, such as acid-base reactions or precipitation reactions, are not redox reactions.

In a reaction, oxidation can occur independently of reduction. This is wrong because oxidation and reduction always occur together in a redox reaction. There cannot be oxidation without a corresponding reduction to balance the electron transfer.

Explanation:

Alkali metals have a single valence electron that they readily lose, while halogens have seven valence electrons and readily gain one electron to achieve a stable octet. When they react, the alkali metal transfers its valence electron to the halogen, resulting in the formation of a cation (alkali metal) and an anion (halogen). These oppositely charged ions are held together by electrostatic attraction, forming an ionic bond. Sharing electrons occurs in covalent bonds, not in this reaction.

Correct Answer:

an electron transfers from the alkali metal to the halogen

Why Other Options Are Wrong:

an electron transfers from the halogen to the alkali metal. This is incorrect because halogens gain electrons, not lose them, and alkali metals are the electron donors.

the alkali metal and the halogen share a single electron. This is false because the reaction forms an ionic bond, not a covalent bond with shared electrons.

the alkali metal and the halogen share two electrons. This is wrong because this describes a double covalent bond, which does not occur between alkali metals and halogens.

the alkali metal and the halogen form an ionic bond with no transfer of an electron from one to the other. This is incorrect because the defining feature of an ionic bond is electron transfer; without electron transfer, the bond would not be ionic.

Explanation:

The Aufbau Principle states that electrons occupy the lowest energy orbitals available first before filling higher energy orbitals. This systematic filling minimizes the total energy of the atom and determines the ground-state electron configuration. The other options are incorrect because they either suggest filling starts from the highest energy (which is opposite), occurs randomly, or incorrectly describes the order of orbital filling across energy levels.

Correct Answer:

Electrons occupy the lowest energy orbitals available before filling higher energy orbitals

Why Other Options Are Wrong:

Electrons fill orbitals in order of increasing energy, starting from the highest energy level. This is incorrect because filling begins with the lowest energy level, not the highest.

Electrons are added to orbitals in a random manner without regard to energy levels. This is false because electron filling follows a specific order dictated by orbital energies.

Electrons fill all orbitals of a given energy level before moving to the next higher level. This is misleading because electrons do not necessarily fill all orbitals of a principal energy level first; they fill subshells in order of increasing energy, which may span multiple principal energy levels.

Explanation:

Primary chemical bonds include ionic, covalent, and metallic bonds, which involve the actual formation of stable electron interactions that hold atoms together in compounds or metals. A hydrogen bond, on the other hand, is considered a secondary or intermolecular force. It is weaker than primary bonds and occurs between molecules rather than within a molecule or lattice. Therefore, hydrogen bonding is an exception when listing primary bonding types.

Correct Answer:

Hydrogen bond

Why Other Options Are Wrong:

Ionic bond. This is incorrect because ionic bonding is a primary bond formed by the electrostatic attraction between cations and anions.

Metallic bond. This is wrong because metallic bonding is a primary bond, characterized by the attraction between metal cations and delocalized electrons in a lattice.

Covalent bond. This is incorrect because covalent bonding is a primary bond formed through the sharing of electrons between atoms.

Explanation:

Hund's rule states that electrons will fill degenerate orbitals (orbitals of the same energy) singly and with parallel spins before pairing occurs. This minimizes electron-electron repulsion and results in the lowest energy configuration for the atom. Hund's rule applies specifically to the filling of p, d, and f orbitals in accordance with the Aufbau principle and is crucial for predicting the electron configuration of atoms and ions.

Correct Answer:

Electrons will occupy separate degenerate orbitals and maintain parallel spins before pairing up.

Why Other Options Are Wrong:

Electrons in outer energy levels will experience a lesser degree of nuclear charge. This is incorrect because it describes the shielding effect, not Hund’s rule.

No two electrons may share the same set of quantum numbers. This is wrong because it describes the Pauli exclusion principle, which is a different rule governing electron configurations.

The location and the momentum of an electron cannot be known simultaneously. This is incorrect because it refers to the Heisenberg uncertainty principle, which is unrelated to Hund’s rule.

Explanation:

The Earth’s crust is primarily composed of silicate minerals, which are compounds of silicon and oxygen, often combined with aluminum and iron. Silicon and oxygen form the basic framework of most minerals, while aluminum and iron are common cations in these structures. Helium, sulfur, carbon, and zinc are either rare or not significant components of the crust, making the second option the correct description of the major elemental composition.

Correct Answer:

silicon, oxygen aluminum, and iron

Why Other Options Are Wrong:

helium, oxygen, and aluminum. This is incorrect because helium is a noble gas present in trace amounts and does not form minerals; it is not a significant crustal element.

sulfur, oxygen, iron, and magnesium. This is wrong because although sulfur, iron, and magnesium are present in some minerals, they are not the primary elements in the majority of Earth's crust minerals.

silicon, oxygen carbon, and zinc. This is false because carbon and zinc are minor components; carbon is mainly in organic matter or carbonates, and zinc occurs in trace amounts, not as major crustal elements.

Explanation:

An oxidizing agent is a substance that accepts electrons from another species during a redox reaction. By gaining electrons, it undergoes reduction and causes another species to be oxidized. This is the defining characteristic of an oxidizing agent. The other options are incorrect because they either describe the behavior of a reducing agent, suggest no change occurs, or imply it only facilitates the reaction without actual electron transfer.

Correct Answer:

A substance that gains electrons and decreases its oxidation state

Why Other Options Are Wrong:

A substance that loses electrons and increases its oxidation state. This describes a reducing agent, not an oxidizing agent.

A substance that remains unchanged during the reaction. This is incorrect because an oxidizing agent must undergo a change in oxidation state by gaining electrons.

A substance that facilitates the reaction without participating in electron transfer. This is false because an oxidizing agent actively participates by accepting electrons, not merely facilitating the reaction.