The question asks to identify the type of octet rule deviation observed in the boron atom of a BF3 molecule. We need to analyze the Lewis structure of BF3 and count the number of electrons around the central boron atom.
C) An incomplete octet: As determined in the step-by-step analysis, the central boron atom in BF3 has only 6 valence electrons around it, which is less than the required 8 electrons for a complete octet. Therefore, it is an example of a molecule with an incomplete octet.
The question asks to classify molecules like NO and NOâ‚‚, which contain an unpaired electron. We need to understand the electron configuration and bonding characteristics of these molecules to determine the correct category.
Correct Option: C) Odd-electron molecules. Molecules like NO and NOâ‚‚ have an odd number of total valence electrons (11 for NO and 17 for NOâ‚‚), which means they must contain at least one unpaired electron. This characteristic defines them as odd-electron molecules.
The question asks what a Lewis dot symbol represents for an atom. Lewis dot symbols are a fundamental concept in chemistry used to visualize the bonding behavior of atoms. Understanding their purpose is key to answering this question.
Correct Option: A) A Lewis dot symbol for an atom is used to represent its valence electrons. These are the electrons in the outermost shell of an atom, which are primarily involved in chemical bonding.
To determine the number of dots surrounding an atom's symbol in its Lewis dot structure, we need to find the number of valence electrons of that atom. The number of valence electrons for a main group element is equal to its group number (for groups 1, 2, and 13-18) or can be determined from its electron configuration.
Correct Option: D) 5
The question asks for the complete formula to calculate the formal charge on an atom. Formal charge is a concept used in chemistry to determine the most plausible Lewis structure for a molecule. It helps in understanding the distribution of electrons and the stability of a molecule.
A) Half of the bonding (shared) electrons
This correctly completes the formula for formal charge. The bonding electrons are shared between two atoms, so only half of them are considered to belong to the specific atom when calculating its formal charge.
To determine the formal charge on an atom in a Lewis structure, we use a specific formula that considers the number of valence electrons, non-bonding electrons, and bonding electrons. We will apply this formula to the carbon atom in the given Lewis structure of carbon dioxide (O=C=O).
B) 0 — The calculation shows that the formal charge on the carbon atom in the O=C=O structure is 0.