Which one of the following orders represents the correct sequence of increasing basic nature of the given oxides?

Of the following pairs,the one containing an example of metalloid elements in the periodic table is:

Match the following:

Oxide	Nature
$a$. $CO$	$i$. Basic
$b$. $BaO$	$ii$. Neutral
$c$. $Al_2O_3$	$iii$. Acidic
$d$. $Cl_2O_7$	$iv$. Amphoteric

Which of the following is the correct option?

Which of the following is the most electropositive element?

The correct order of the metallic character of the elements $Be, Al, Na, K$ is

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.