What is the maximum number of elements possible in a period? Where are they located?

Atomic numbers of three elements $E_1$,$E_2$ and $E_3$ of the periodic table are $Z_1$,$50$ and $Z_2$ respectively. From the position of the elements shown in the figure,the value of $(Z_2 - Z_1)$ is:

Based on the provided periodic table segment,identify the correct statement.

Which among the following electronic configurations belong to main group elements?
$A. [Ne] 3s^1$
$B. [Ar] 3d^3 4s^2$
$C. [Kr] 4d^{10} 5s^2 5p^5$
$D. [Ar] 3d^{10} 4s^1$
$E. [Rn] 5f^0 6d^2 7s^2$
Choose the correct answer from the options given below:

Identify the incorrect match :

Temporary Systematic Name	$IUPAC$ Official Name
$a$. Unnilunium $(101)$	$i$. Mendelevium $(Md)$
$b$. Unniltrium $(103)$	$ii$. Lawrencium $(Lr)$
$c$. Unnilhexium $(106)$	$iii$. Seaborgium $(Sg)$
$d$. Ununnilium $(110)$	$iv$. Darmstadtium $(Ds)$

Write the general outer electronic configuration of $s$-,$p$-,$d$- and $f$-block elements.