Ascientist has isolated a fatty acid that has 26 carbons. most of the carbon atoms in the fatty acid chain are connected by single bonds, except there is a double bond between the number 3 and 4 carbons as well as the number 9 and 10 carbons. the only other elements in the compound are hydrogen and oxygen. based on this information, the compound is a fatty acid.

            Based on giveninformation, the compound is a Poly Unsaturated fatty acid.

Explanation:
                   Fatty acids are carboxylic acids with -COOH functional group and a chain of hydrocarbons.

Fatty Acids are classified as,

i) Saturated Fatty Acids:
                                      Those Fatty Acids in which there is no double bond between the carbon chain are called as saturated fatty acids. 

Examples:
                 Lauric Acid           CH₃(CH₂)₁₀COOH

                 Myristic Acid         CH₃(CH₂)₁₂COOH

                 Palmitic Acid         CH₃(CH₂)₁₄COOH

ii) Unsaturated Fatty Acids:
                                      Those Fatty Acids in which contain a single double bond (mono-unsaturated) or more than one double bond (poly-unsaturated) d between the carbon atoms in a chain are called as unsaturated fatty acids. 

Examples:
                 Linoleic acid

                 Vaccenic acid

                 Palmitoleic acid

The saturated fatty acid containing 26 carbon atoms is called as Cerotic acid. While cerotic acid containing a double bond at position 3 and 9 has a IUPAC name Hexacosa-3,9-dienoic acid with following structure.

1s22s22p63s2- Magnesium

1s22s22p63s23p3- phosphorus

1s22s22p63s23p64s23d104p6- krypton

1s22s2- Beryllium

1s22s22p6- neon

1s22s22p3- nitrogen

Explanation:

The identity of an element is deducible from its electronic configuration by looking out for the outermost shell configuration and counting the total number of electrons present. for example; phosphorus 15 electrons and an outermost shell configuration of ns2 np3. Any electronic configuration written above which reflects these characteristics must belong to phosphorus.