Is it possible for the atom of an element to have one electron,one proton,and no neutron? If so,name the element.

Elements with valency $1$ are

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

In what way is the Rutherford's atomic model different from that of Thomson's atomic model?

An atom of an element $X$ may be written as ${ }_{4}^{9} X$.
$(a)$ What does the figure $9$ indicate?
$(b)$ How many neutrons does this element $X$ contain?

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?