There are many. One with only oxygen and carbon would be carbonyl with a carbon double bonded to an oxygen.
A carboxyl group. Refer to the related link below for an illustration.
carboxylic acid
Amine
ester
Phosphate group.
Carbonyl
Formaldehyde, as its name implies, is an aldehyde. Thus, it contains a carbonyl (CHO) functional group. This group consists of a carbon atom double bonded to an oxygen atom. The carbonyl group is the only functional group contained in formaldehyde.
At the end of the molecule C is equal to O it is an aldehyde. Carbon has 3 bonds to form and an alcohol would have COH2. The last section is CO and the Carbon and Oxygen are double bonded.
Examples are oxygen, nitrogen , alkenes with carbon carbon double bonds, alkynes with carbon carbon triple bonds, the carbon oxygen double bonds in carbon dioxide
Phosphate group.
Carbonyl
>C=O group or keto group
A carbon-oxygen group like this is referred to as a carbonyl group by itself. Any molecule that has one bonded into it's main chain is a ketone.
Formaldehyde, as its name implies, is an aldehyde. Thus, it contains a carbonyl (CHO) functional group. This group consists of a carbon atom double bonded to an oxygen atom. The carbonyl group is the only functional group contained in formaldehyde.
They both fall under the Organic Functional Group "amide", meaning they both have a double bonded oxygen and a nitrogen + a hydrogen attached to a carbon.
At the end of the molecule C is equal to O it is an aldehyde. Carbon has 3 bonds to form and an alcohol would have COH2. The last section is CO and the Carbon and Oxygen are double bonded.
Examples are oxygen, nitrogen , alkenes with carbon carbon double bonds, alkynes with carbon carbon triple bonds, the carbon oxygen double bonds in carbon dioxide
Both carbon skeletons and functional groups put together, add, or have atomos of oxygen, hydrogen, and carbon. Different arrangements of atoms bonded to a carbon skeleton can form functional groups, wich give specific properties to molecules.
There are two oxygen double bonded to one carbon. DOUBLE BOND.
CH2O, one carbon atom in the middle and from that 2 hydrogen atoms and one oxygen double bonded to the carbon. it is a planar molecule with angles of 108 (from one hydrogen to the other hydrogen) and 126 (from the oxygen to both hydrogen)
Both aldehydes and ketones contain a C=O (carbon double bond oxygen). Ketones have this C=O somewhere in their carbon chain, but not at the start or end of the chain (ie: there are more carbons attached to the carbon containing the double bond oxygen, and no hydrogens bonded to that carbon). Aldehydes have there C=O at the end, or start of the chain, and to maintain the octet rule, there is hydrogen bonded to the oxygen containing carbon (please note that it is a C=O). The functional group of alcohol is OH. This OH is bonded directly to the last (or first) carbon in the chain. The big difference is that the carbon bond oxygen is a single bond and the hydrogen is bonded to the oxygen (not the carbon, as the case of aldehydes).