Fluorine,chlorine,bromine and iodine are placed in the same group $(17)$ of the periodic table,because

Observe the following statements:
$I$. The physical and chemical properties of elements are periodic functions of their electronic configuration.
$II$. Electronegativity of fluorine is less than the electronegativity of chlorine.
$III$. Electropositive nature decreases from top to bottom in a group.
The correct answer 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.

Which of the following pairs shows opposite trends when moving from left to right in a period and from top to bottom in a group?

Match the items in List-$I$ with the items in List-$II$:

List-$I$	List-$II$
$(A)$ Rubidium	$(1)$ Germanium
$(B)$ Platinum	$(2)$ Radioactive chalcogen
$(C)$ Eka-silicon	$(3)$ $s$-block element
$(D)$ Polonium	$(4)$ Atomic number $78$

Which of the following sequences represents the atomic numbers of only representative elements?