In the atom of an element $X$,$6$ electrons are present in the outermost shell. If it acquires noble gas configuration by accepting the requisite number of electrons,what would be the charge on the ion so formed?

$(a)$ Name the three subatomic particles of an atom.
$(b)$ An atom of an element has $5$ electrons in the $L$ shell.
$(i)$ What is the atomic number of the element?
$(ii)$ State its valency.
$(iii)$ Identify the element and write its name.

If $Z = 3$,what would be the valency of the element? Also,name the element.

State three rules suggested by Bohr and Bury for the distribution of electrons into different orbits (shells) of an atom.

$A$ helium atom has two electrons in its valence shell,but its valency is not two. Explain.

What do you understand by an octet of electrons in the valence shell?