Respuesta :

the main formula is as follow  is explained in the attached file  (please look at the examples)

the 1,3- butadiene is h2c=ch-ch=ch2, so we have 

sp²             sp²     sp²               sp²
h2c    =     ch   -     ch         =      ch2

the hybridization of the carbon atoms  is sp²  : trigonal planar