Write the names given to the vertical columns and horizontal rows in the Modern Periodic Table. How does the metallic character of the elements vary on moving down a vertical column? How does the size of the atomic radius vary on moving from left to right in a horizontal row? Give reason in support of your answer in the above two cases.

On the basis of the periodic classification, identify each set belonging to either a group or a period.

$\mathrm{Na}, \mathrm{K}, \mathrm{Rb}$

On the basis of the periodic classification, identify each set belonging to either a group or a period.

$\mathrm{B}, \mathrm{C}, \mathrm{N}$

On the basis of the periodic classification, identify the given set belonging to either a group or a period.

$\mathrm{He}, \mathrm{Ne}, \mathrm{Ar}$

The formula of magnesium oxide is $\text{MgO}$. The formula of magnesium chloride can be written as ${\mathrm{Mg}}_{\mathrm{x}}{\mathrm{Cl}}_{\mathrm{y}}$

The value of x and y in the formula can be-

A. x = 1, y = 1

B. x = 1, y = 2

C. x = 2, y = 1

"Enter your correct answer as A, B or C."