CHEM 3300 BWT1 Inorganic Chemistry

Explanation:

Atomic radius generally increases as the number of energy levels (electron shells) increases, because electrons are added farther from the nucleus, reducing the effective nuclear attraction on the outer electrons. This explains why elements in lower periods of the periodic table have larger radii than those in higher periods. The other statements are false because ionic radius can be smaller (for cations) or larger (for anions) than the atomic radius, chemical activity is influenced by atomic radius, and atoms vary significantly in size depending on their element and position in the periodic table.

Correct Answer:

As the number of energy levels increases in an atom, the atomic radius increases

Why Other Options Are Wrong:

Ionic radius is always larger than the atomic radius. This is incorrect because cations are smaller than their neutral atoms, while anions are larger; it is not always larger.

Chemical activity does not depend on atomic radius. This is false because atomic radius affects the ability of atoms to lose or gain electrons, influencing reactivity.

All atoms are very small and, therefore, are about the same size. This is wrong because atomic sizes vary widely across the periodic table, influenced by nuclear charge and electron configuration.

Explanation:

The arrangement of electrons in an atom’s orbitals, also known as its electronic configuration, directly influences how the atom interacts with other atoms. Electrons in the outermost shell, or valence electrons, determine the atom’s ability to form chemical bonds, its reactivity, and the types of compounds it can participate in. Elements with similar valence electron configurations often exhibit similar chemical properties. The arrangement of electrons does not determine the atom’s mass or density, nor does it solely dictate color or appearance, although electron transitions can influence some spectroscopic properties.

Correct Answer:

It influences the atom's reactivity and bonding capabilities.

Why Other Options Are Wrong:

It determines the atom's mass and density. This is incorrect because the mass and density of an atom are determined by the number of protons and neutrons in the nucleus, not by the arrangement of electrons.

It has no effect on the atom's behavior in reactions. This is wrong because electron arrangement is fundamental to chemical reactivity. The number and position of valence electrons directly dictate how atoms interact in chemical reactions.

It solely dictates the atom's color and appearance. This is incorrect because while electronic transitions can affect color, chemical properties such as bonding and reactivity are primarily governed by electron configuration, not visual appearance alone.

Explanation:

Metallic bonding is characterized by a delocalization of all valence electrons across a lattice of metal atoms. This “sea of electrons” allows metals to conduct electricity, be malleable, and exhibit other metallic properties. The bonding is not localized between specific atoms, unlike covalent bonds, and does not involve transferring electrons to create ions, unlike ionic bonds. This delocalized electron model explains the strength and flexibility of metallic structures.

Correct Answer:

a delocalization of all valence electrons throughout the entire lattice of metal atoms.

Why Other Options Are Wrong:

an attraction of oppositely charged particles following the exchange of electrons between metal atoms. This describes ionic bonding, not metallic bonding. Metallic bonding does not involve full electron transfer creating ions.

an equal sharing of electrons between two metal atoms. This describes a covalent bond, which is localized between two atoms. Metallic bonding involves delocalized electrons, not shared pairs.

an unequal sharing of electrons between metal atoms. This is incorrect because metallic bonds are not based on unequal electron sharing; that concept applies to polar covalent bonds. Metallic bonding involves delocalized electrons free to move across the lattice.

Explanation:

Oxidation states are formal charges assigned to atoms in a compound that indicate the hypothetical number of electrons an atom has gained, lost, or shared relative to its elemental state. Chemists follow a set of systematic rules to determine these states, considering factors such as known oxidation numbers of elements, the electronegativity differences between atoms, and the types of bonds formed. The key is that these are rules-based assignments rather than direct physical measurements like counting protons or valence electrons. This ensures consistent interpretation of redox reactions and electron distribution in compounds.

Correct Answer:

Oxidation states are assigned according to a set of rules that account for the gain, loss, or sharing of electrons in a compound.

Why Other Options Are Wrong:

Oxidation states are assigned based on the total number of protons in the nucleus of an atom. This is incorrect because oxidation states have nothing to do with the number of protons. They are related to the electron distribution in chemical bonding, not nuclear properties.

Oxidation states are determined by the number of electrons an atom has in its outermost shell. This is wrong because the oxidation state can differ from the actual valence electrons, especially in molecules where electrons are shared or transferred. It is a formalism, not a direct count of valence electrons.

Oxidation states are calculated by considering the electronegativity of the atoms and the type of bonds formed. While electronegativity influences bond polarity and can inform oxidation states, this option is incomplete. Oxidation states are formally assigned using a set of explicit rules, not just by considering electronegativity and bond type.

Explanation:

The tendency of an atom to lose electrons and form a cation is directly related to its metallic character. Metals have low ionization energies, meaning they can easily lose electrons to form positive ions. Therefore, the metallic characteristic reflects the ease with which an atom loses electrons. Ionization energy is also related, but the metallic character more broadly describes the general chemical behavior of elements, including their cation-forming tendency.

Correct Answer:

Metallic Characteristic

Why Other Options Are Wrong:

Atomic Radius. This is incorrect because atomic radius indicates the size of an atom, not directly its tendency to lose electrons, although larger atoms tend to lose electrons more easily.

Ionization Energy. While related, this is a quantitative measure of energy required to remove an electron, not the broader periodic trend indicating cation formation tendency.

Electronegativity. This is wrong because electronegativity measures an atom's ability to attract electrons, not to lose them.Electron Affinity. This is incorrect because electron affinity describes the energy change when an atom gains an electron, the opposite of losing one.

Non-metallic Characteristic. This is wrong because non-metals tend to gain electrons to form anions, not lose electrons to form cations.

Explanation:

Metals are characterized by their malleability (ability to be hammered into sheets) and ductility (ability to be drawn into wires), which are physical properties that distinguish them from non-metals. Non-metals, in contrast, are generally brittle in solid form and break easily when subjected to stress. This distinction in mechanical properties is one of the primary ways to differentiate metals from non-metals in practical and chemical contexts.

Correct Answer:

Metals are malleable and ductile, while non-metals are usually brittle.

Why Other Options Are Wrong:

Metals are typically brittle and have low melting points. This is incorrect because metals are malleable and ductile, and many have high melting points. Brittle behavior is characteristic of non-metals, not metals.

Non-metals are generally good conductors of electricity and heat. This is wrong because non-metals are poor conductors, unlike metals which conduct heat and electricity efficiently.

Non-metals can be easily shaped and drawn into wires. This is incorrect because non-metals are brittle and cannot be shaped or drawn into wires, unlike metals.

Explanation:

Ionization energy is the energy required to remove an electron from a gaseous atom or ion. Across a period, ionization energy generally increases because the nuclear charge increases while electrons are added to the same principal energy level, pulling electrons closer and making them harder to remove. Down a group, ionization energy decreases because electrons are added to higher energy levels farther from the nucleus, where they experience less attraction from the positively charged nucleus, making them easier to remove. This trend is a key characteristic of periodic properties in the periodic table.

Correct Answer:

Ionization energy increases across a period and decreases down a group.

Why Other Options Are Wrong:

Ionization energy decreases across a period and increases down a group. This is incorrect because the trend across a period is the opposite; ionization energy increases, not decreases, due to increasing nuclear charge.

Ionization energy remains constant across a period and increases down a group. This is wrong because ionization energy varies across a period, increasing from left to right.

Ionization energy increases down a group and decreases across a period. This is incorrect because ionization energy actually decreases down a group and increases across a period, not the reverse.

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:

A redox reaction involves the transfer of electrons from one species to another. The species that loses electrons is oxidized, while the species that gains electrons is reduced. This electron transfer is central to many chemical processes, including combustion, corrosion, and cellular respiration. Other types of transfers, such as protons, ions, or whole atoms, do not define a redox reaction, although they may occur in other reaction types.

Correct Answer:

The transfer of electrons between two species

Why Other Options Are Wrong:

The transfer of protons between two species. This describes acid-base reactions, not redox reactions.

The transfer of ions between two species. This is incorrect because redox reactions specifically involve electrons, not entire ions.

The transfer of atoms between two species. This is false; atom transfer occurs in some reactions (like synthesis or displacement) but is not the defining feature of a redox reaction.