If the valence shell electronic configuration for an element is $ns^2 np^5$,this element will belong to the group of

Which of the following is the strongest acid?

Use the periodic table to answer the following questions.
$(a)$ Identify an element with five electrons in the outer subshell.
$(b)$ Identify an element that would tend to lose two electrons.
$(c)$ Identify an element that would tend to gain two electrons.
$(d)$ Identify the group having metal,non-metal,liquid as well as gas at room temperature.

Arrange the following acids in the decreasing order of their acidic strength: $Cl(OH) \ (I)$,$Br(OH) \ (II)$,$I(OH) \ (III)$.

Which of the following pairs has elements containing the same number of electrons in the outermost orbit?

$HClO_4$ is a stronger acid than $H_2SO_4$ due to which of the following reasons?
$1$. Oxidation state of $Cl$ in $HClO_4$ is $+7$ and that of $S$ in $H_2SO_4$ is $+6$.
$2$. $Cl$ is more electronegative than $S$.
$3$. $HClO_4$ is monobasic,whereas $H_2SO_4$ is dibasic.
$4$. $ClO_3$ part of $HClO_4$ can break $O-H$ bond more easily to liberate a proton than $SO_3$ part in $H_2SO_4$.