Fill in the blanks:
$(i)$ Atoms and ions having the same number of electrons are known as ........... .
$(ii)$ The quantitative measure of the tendency of an element to lose an electron is called ........... .
$(iii)$ The screening effect is also known by the name ........... .
$(iv)$ The enthalpy change when a gaseous neutral atom forms a negative ion is called ........... .

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:

Which of the following statements are correct?
$(i)$ First ionisation enthalpy of $He < $ Second ionisation enthalpy of $Li$.
$(ii)$ $Li$ has the highest second ionisation enthalpy.
$(iii)$ All $d$-block elements are transition elements.
$(iv)$ The only alphabet not found in the periodic table is the letter '$J$'.
$(v)$ Francium concentration is $\sim 10^{-18} \ ppm$ on Earth.

If the period number and group number of any representative element are the same,then which of the following statements is incorrect regarding such type of element in its ground state? (Period number and group number are according to the modern form of the periodic table)

Based on the provided image, identify the correct option for the elements $A, B, C, D, E$ given that $C$ has the electronic configuration $[Xe] \ 6s^2 \ 5d^1$.

As we go from left to right in period $2$ of the periodic table,the gram atomic volume of the elements: