Identify the $Mg^{2+}$ ion from the figures,where $n$ and $p$ represent the number of neutrons and protons,respectively.

In a sample of ethyl ethanoate $(CH_3COOC_2H_5)$,the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?

Give reasons for the following:
$(a)$ Ions are more stable than atoms.
$(b)$ Noble gases show low reactivity.

The charge on an electron is equal to

In the Thomson's model of atom,which of the following statements are correct?
$(i)$ The mass of the atom is assumed to be uniformly distributed over the atom.
$(ii)$ The positive charge is assumed to be uniformly distributed over the atom.
$(iii)$ The electrons are uniformly distributed in the positively charged sphere.
$(iv)$ The electrons attract each other to stabilize the atom.

Give a reason to explain why
$(a)$ isotopes of an element show identical chemical properties?
$(b)$ the atomic masses of elements are in fractions?
$(c)$ atoms combine with other atoms?