One electron is present in the outermost shell of the atom of an element $X$. What would be the nature and value of charge on the ion formed if this electron is removed from the outermost shell?

Find out the valency of an element $X$ having atomic number $16$.

Rutherford's $\alpha-$ particle scattering experiment showed that
$(i)$ Electrons have negative charge
$(ii)$ The mass and positive charge of the atom is concentrated in the nucleus
$(iii)$ Neutron exists in the nucleus
$(iv)$ Most of the space in atom is empty
Which of the above statements are correct?

Match the names of the scientists given in column $A$ with their contributions towards the understanding of the atomic structure as given in column $B$.

Column $A$	Column $B$
$(a)$ Ernest Rutherford	$(i)$ Indivisibility of atoms
$(b)$ $J$.$J$. Thomson	$(ii)$ Stationary orbits
$(c)$ Dalton	$(iii)$ Concept of nucleus
$(d)$ Neils Bohr	$(iv)$ Discovery of electrons
$(e)$ James Chadwick	$(v)$ Atomic number
$(f)$ $E$. Goldstein	$(vi)$ Neutron
$(g)$ Mosley	$(vii)$ Canal rays

The number of valence electrons in $Cl^{-}$ ion are

Enlist the conclusions drawn by Rutherford from his $\alpha -$ ray scattering experiment.