(also written as ) is the formula for the acetate ion. Most polyatomic ions tend to follow certain naming trends, but acetate is one of the ions that does not follow those naming trends, so memorize this one since it shows up frequently in chemistry.

The alcohol functional group is -OH

We know that by definition, all amino acids contain a carboxylic acid functional group (), and an amino functional group (). Therefore the additional functional group can only contain sulfur and hydrogen.

The amino functional group is slightly basic, and the carboylic acid functional group is slightly acidic. The -SH functional group will also be acidic, but because sulfur and oxygen are in the same group on the periodic table, the -SH group will have similar acidic properties to an -OH group, and alcohols are less acidic than carboxylic acids.

Amides contain both oxygen and nitrogen in the functional group. The oxygen forms a double bond with a carbon, and the carbon bonds to a nitrogen. This forms the structure , where the nitrogen is also bound to the carbon.

is an alcohol functional group.

is an amine functional group.

is a carboxylic acid functional group.

is an aldehyde functional group.

A nitrile group contains a carbon-nitrogen triple bond, while all of the other groups contain a carbon-oxygen double bond.

Nitrile:

Ester:

Ketone:

Carboxylic acid:

Aldehyde:

An organic compound is typically defined as one that contains carbon. Though there some small exceptions to this rule (for example, cyanide is not considered organic), in general most compounds follow it. 

Though water, oxygen, and sodium chloride, may seem organic, they are not for they do not contain any covalent bonds to carbon. The only gievn compound that contains carbon is glucose, a sugar. 

The simplest way to begin these types of problems is to assume that we are starting out with 100 grams of the sample compound. This allows us to simplify things, since we know the mass percentages of the elements that make up out unknown compound.

Next, we must convert amount of each element from grams into moles.

This gives us a formula of 

Now, we need to simplify this formula by dividing each of the terms by the greatest common denominator, 3.33, which gives us:

This is our empirical formula. To obtain the molecular formula, we must first find the mass of our empirical formula, which is .

Next, we need to divide the molecular weight of the compound by the empirical weight to obtain an integer of . Finally, we multiply the empirical formula by this integer in order to obtain the molecular formula, which is:

..            ..

:F — B —  F:         Boron can have a violated octet (6 e^-) and each F has 3 lone pairs

..      |      ..          for a total of 9 pairs of unpaired electrons

        :F:

         .. 

BCl₃ only has six electrons around boron, while NO₂ (with an odd number of electrons) would have only 7 electrons around the central nitrogen.

Lewis dot diagrams can help us keep track on how the valence electrons will disperse themselves among orbitals in the atom. When drawing these diagrams, it is important to keep two things in mind.

1. The s orbital will be filled before the p orbital begins to be filled.

2. Electrons will never pair in the same orbital if an orbital of equal energy is unoccupied.

Knowing these two facts, we can predict which of the following elements will have two unpaired electrons.

Fluorine will have seven valence electrons, meaning that only one orbital will not be completely filled.

Beryllium only has two valence electrons, but they will both be found in the 2s orbital, because it must be filled before the p orbitals can receive electrons.

Nitrogen will have five valence electrons, so two will be found in the 2s orbital. The other three will be present in their own p orbitals, meaning nitrogen has three unpaired electrons.

Neon will have eight valence electrons, fully filling the 2s and 2p orbitals. It will have no unpaires electrons. 

Carbon has one less valence electron than nitrogen, meaning that it will have two unpaired electrons in the p orbitals.