Question

In going from hydrogen to helium, what do the changes in atomic radius (37 to 32 pm) and ionization energy (1311 kJ/mole to 2377 kJ/mole) suggest about the relative magnitudes of the changes in the electron-nucleus attraction and the electron- electron repulsion?

Answer 1

While going from Hydrogen to Helium, it can be seen that the atomic radius is decreasing from 37pm of H to 32pm of He, which means that the size of the atom decreases, meaning thereby that the force of attraction between nucleus and electron increases as we go from H to He, the ionization energy which is the energy required by the atom to lose its outermost electron, also increases while going from H to He, thus it becomes more harder for the atom to lose its electron, implying that the force of attraction between nucleus and electron increases.Also, Hydrogen has 1 electron while Helium has 2 electrons in its shell, thus the electron-electron repulsion also increases from H to He.