Based on the ionization energy levels of element 3, one can tell that the element is Magnesium. Magnesium has an atomic number of 12 so in a neutral atom, that means that there are 12 protons and 12 electrons. So based on the electrons, we can write the electronic configuration as:
[tex] 1s^{2} 2s^{2} 2p^{6} 3s^{2} [/tex]
