How many neutrons are present in the nucleus of $_{88}Ra^{226}$?

Consider an imaginary ion ${}_{22}^{48}X^{3-}$. The nucleus contains '$a$'$\%$ more neutrons than the number of electrons in the ion. The value of '$a$' is $.....$ [nearest integer].

If the mass attributed to a neutron were halved and that attributed to the electron were doubled,the atomic mass of $_6C^{12}$ would

Which of the following is correct?

Which number is common in isotopes?

What is the atomic number and the number of electrons in a hydrogen atom (containing $1$ proton) and a sodium atom (containing $11$ protons) respectively?