Write $IUPAC$ names and calculate the number of $\sigma$ and $\pi$ bonds for the following compounds:
$(i)$ $CH_3-CH(CH_3)-CH=CH-CH_2-CH=C(CH_3)-CH_2-CH_3$
$(ii)$ $CH_3-CH=CH-CH_2-CH=CH-CH(C_2H_5)-CH_2-CH_3$
$(iii)$ $CH_2=C(CH_2-CH_2-CH_3)_2$
$(iv)$ $CH_3-CH(C_4H_9)-CH=C(C_2H_5)-CH_2-CH(CH_3)_2$

The $IUPAC$ name of the given compound is:

Rank the following groups in order of $R, S$ priority (Cahn-Ingold-Prelog priority rules,where $1$ is highest priority):
$A) -CH(CH_3)_2$
$B) -CH_2CH_2Br$
$C) -CH_2Br$
$D) -C(CH_3)_3$

The $IUPAC$ name of $CH_3CH_2C(Br)=CHCl$ is

Fill in the blanks:
$(1)$ ....... model indicates only bonds in a molecule.
$(2)$ Only ......... model of a molecule indicates both bonds as well as atoms.
$(3)$ In the nomenclature of cyclic compounds,the ....... prefix is written before the name of the simple chain containing alkane.
$(4)$ The names of $C_{20}H_{42}$ and $C_{30}H_{62}$ are ........... and .......... respectively.

Write the $IUPAC$ name for the following compound: