Question

Need help asap with this chemistry if someone could help me

Answer 1

Answer:

1)

Structure One:

• N: -2
• C: 0
• O: +1

Structure Two:

• N: 0
• C: 0
• O: -1

Structure Three:

• N: -1
• C: 0
• O: 0.

Structure Number Two would likely be the most stable structure.

2)

• All five C atoms: 0
• All six H atoms to C: 0
• N atom: +1.

The N atom is the one that is "likely" to be attracted to an anion. See explanation.

Explanation:

When calculating the formal charge for an atom, the assumption is that electrons in a chemical bond are shared equally between the two bonding atoms. The formula for the formal charge of an atom can be written as:

$\text{Formal Charge} \\ = \text{Number of Valence Electrons in Element} \\ \phantom{=}-\text{Number of Chemical Bonds} \\\phantom{=} - \text{Number of nonbonding Lone Pair Electrons}$.

For example, for the N atom in structure one of the first question,

• N is in IUPAC group 15. There are 15 - 10 = 5 valence electrons on N.
• This N atom is connected to only 1 chemical bond.
• There are three pairs, or 6 electrons that aren't in a chemical bond.

The formal charge of this N atom will be $5 - 1 - 6 = -2$.

Apply this rule to the other atoms. Note that a double bond counts as two bonds while a triple bond counts as three.

1)

Structure One:

• N: -2
• C: 0
• O: +1

Structure Two:

• N: 0
• C: 0
• O: -1

Structure Three:

• N: -1
• C: 0
• O: 0.

In general, the formal charge on all atoms in a molecule or an ion shall be as close to zero as possible. That rules out Structure number one.

Additionally, if there is a negative charge on one of the atoms, that atom shall preferably be the most electronegative one in the entire molecule. O is more electronegative than N. Structure two will likely be favored over structure three.

2)

Similarly,

• All five C atoms: 0
• All six H atoms to C: 0
• N atom: +1.

Assuming that electrons in a chemical bond are shared equally (which is likely not the case,) the nitrogen atom in this molecule will carry a positive charge. By that assumption, it would attract an anion.

Note that in reality this assumption seldom holds. In this ion, the N-H bond is highly polarized such that the partial positive charge is mostly located on the H atom bonded to the N atom. This example shows how the formal charge assumption might give misleading information. However, for the sake of this particular problem, the N atom is the one that is "likely" to be attracted to an anion.