Atoms of chemical elements having same atomic mass but a different atomic number are called Isobars. The sum of the number of protons and neutrons together form the atomic mass. Therefore, we can also say the number of nucleons present in the nucleus is equal to the atomic mass of an atom. It will have the same number of nucleons. The number of protons and neutrons alone will vary but the number of nucleons or the sum of protons and neutrons in isobars will always be same. Isobars always have different atomic structure because of the difference in atomic numbers. The number of neutrons makes up the difference in the number of nucleons. Therefore, they are always different chemical elements having same atomic masses. Thus, isobar has different chemical properties. For example : Iron and nickel have atomic number 26 and 28 respectively. However, the mass number is 58. Argon and calcium with atomic number 18 and 20, respectively. However, they have the same atomic mass 40.
A homologous series is a group of organic compounds having similar structures and similar chemical properties in which the successive compounds differ by (CH2).
Meaning of Homologous Series
A homologous series refers to a series of carbon compounds which have a different number of carbon atoms. However, they contain the same functional group.
In this series, a group of compounds share similar basic chemical makeup. Also, in such a series, the compounds show a difference in the number of iterations of a certain aspect of their structure.
Properties of Homologous Series
Repeating unit is the most important characteristic of a homologous series. An example can be the alkaline group which consists of the CH2 repeating unit.
What this means is that the compounds are identical with the notable exception of the number of CH2 units existing in the compound.
Organic compounds certainly have functional groups. Moreover, these groups define the fundamental and basic properties of the compound.
Most noteworthy, every compound in the homologous series is in the same functional group. However, these compounds have different numbers of repeating units.
Question 1. What is the general formula for aldehydes?
Answer : Aldehydes contain an alkyl group or a hydrogen group that contains a benzene ring in addition to one hydrogen atom that is attached to the carbonyl group. Aldehyde has the generic formula CnH2n+1CHO or CnH2nO because alkene has the universal formula Cn H2n+1.
Question 2 : What does it indicate when a series is homologous to another?
Answer : A group of hydrocarbons that share the same general formula and exhibit chemical properties that are comparable to one another is called a homologous series. There are three distinct hydrocarbon series that is: alkanes, alkenes, and cycloalkanes. Only hydrogen and carbon make up hydrocarbons. A sequence of carbon compounds that share an overall structure but differ in the number of carbon atoms that they contain is known as a homologous series.
On the other hand, both of them have the same functional group. A collection of chemicals in this series have a fundamental chemical composition that is comparable to one another.