Give a brief account on Shakespearean sonnets as a departure from Petrarchan tradition.

If I understand your question correctly, you are asking for an explanation on how Shakespeare revised the format of a sonnet from its pre-existing form as a Petrarchan sonnet. 

First of all, let's discuss what Shakespeare retained of the original version. Both varieties of sonnet use iambic pentameter for their rhythm, and both contain a total of 14 lines. However, from there, they begin to diverge: 

• 
  Stanzas:The Petrarchan stanza is composed of two stanzas,...

If I understand your question correctly, you are asking for an explanation on how Shakespeare revised the format of a sonnet from its pre-existing form as a Petrarchan sonnet. 

First of all, let's discuss what Shakespeare retained of the original version. Both varieties of sonnet use iambic pentameter for their rhythm, and both contain a total of 14 lines. However, from there, they begin to diverge: 

• 
  Stanzas: The Petrarchan stanza is composed of two stanzas, an octave (8 lines) and a sestet (14 lines). The Shakespearean stanza has four stanzas: three quatrains (4 lines) and one couplet (2 lines).


• 
  Rhyme Scheme: Petrarchan sonnets have the following rhyme scheme: ABBAABBA/CDECDE. Shakespearean sonnets are more diverse, using ABAB/CDCD/EFEF/GG. 


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  Content: In a Petrarchan sonnet, the octave tends to present a situation or dilemma, and then the sestet concludes or resolves it. Shakespearean sonnets, having more parts, first introduce a conflict or situation, then expand upon it, next introduce some sort of twist or unexpected element, and finally conclude or resolve the matter.