Quiz 2 - Covalent Bonding and Compounds | Covalent Bonding and Molecular Structure
General Chemistry 1 - Quiz 2 - Covalent Bonding and Compounds
Which of the following is NOT a typical characteristic of covalent compounds?
Covalent compounds typically exist as molecules rather than crystal lattices. The sharing of electron pairs between atoms in covalent compounds leads to discrete molecular structures, unlike ionic compounds which form extensive crystal lattice structures.
Which of the following correctly names the molecular compound P4O10?
The compound P4O10 is named tetraphosphorus decoxide because it consists of four phosphorus atoms and ten oxygen atoms. The prefix 'tetra-' indicates four and 'deca-' indicates ten.
Which principle explains the tendency of atoms in molecules to have eight electrons in their valence shell?
The Octet Rule states that atoms in molecules tend to surround themselves with eight electrons in their valence shells to achieve a noble gas electron configuration. This is a general trend observed in most covalent compounds.
Which of the following is a valid Lewis structure for the nitrogen molecule (N2)?
Nitrogen molecules (N2) form a triple bond with one lone pair on each nitrogen atom. This gives each nitrogen atom a total of eight valence electrons, satisfying the Octet Rule, and reflects the actual bonding found in molecular nitrogen.
When is it appropriate to assign a formal charge to an atom in a Lewis structure?
Formal charge is assigned when an atom in a molecule does not have the same number of valence electrons as it would have as a lone atom. It is calculated based on the difference between the number of valence electrons on the neutral atom and the number of electrons it 'owns' in a given Lewis structure.
Which of the following best illustrates the concept of resonance in molecular structures?
Resonance refers to the phenomenon where a molecule cannot be adequately described by a single Lewis structure and must be represented by two or more structures. These structures, known as resonance forms, are essentially hybrids that reflect the molecule's actual electron distribution.
Which molecule is an example of an exception to the Octet Rule due to having less than eight electrons?
BF3, boron trifluoride, is an example of a molecule where the central boron atom has fewer than eight valence electrons, only having six. Boron often forms compounds that are exceptions to the Octet Rule due to its electron deficiency.
Which of the following species will most likely have a Lewis structure with an expanded octet?
Sulfur hexafluoride (SF6) contains a central sulfur atom that exceeds the typical octet requirement by having six bonds to fluorine atoms. This is possible because sulfur is in Period 3 and has available d-orbitals to accommodate more than eight electrons.
In naming the binary compound Cl2O7, what is the appropriate prefix for oxygen?
The prefix 'hepta' indicates seven atoms of oxygen in the binary compound Cl2O7, therefore the correct name would be dichlorine heptoxide.
In the molecule SF4, how many lone pairs of electrons are on the sulfur atom?
In sulfur tetrafluoride (SF4), sulfur has one lone pair of electrons in addition to the four bonding pairs with fluorine atoms.