Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.
For example, methane, ethane, propane, butane, etc. are all part of the alkane homologous series.
Methane CH4
Ethane CH3CH3
Propane CH3CH2CH3
Butane CH3CH2CH2CH3
There is a difference of −CH2 unit between each successive compound.
Characteristics of homologous series:
All the members of the homologous series have same functional groups and hence similar chemical properties.
Two successive members of a homologous series differ by a −CH2 unit.
Ethene is the first member of the series of alkenes. Its formula is C2H4.F, Cl and Br are the elements each having seven valence electrons. Which of these (i) has the largest atomic radius, (ii) is most reactive? Justify your answer stating reason for each.
An element 'M' has atomic number 11.
(a) Write its electronic configuration.
(b) State the group to which 'M' belongs.
(c) Is 'M' a metal or a non-metal.
(d) Write the formula of its chloride.
When we place a glass prism in the path of a narrow beam of white light a spectrum is obtained. What happens when a second identical prism is placed in an inverted position with respect to the first prism? Draw a labelled ray diagram to illustrate it.
A star sometimes appears brighter and some other times fainter. What is this effect called? State the reason for this effect.