Chemistry - PERIODIC TABLE Question with Solution | TestHub

Element C shows a massive jump between its first and second ionization energies ($I{E}_1=520$ to $I{E}_2=7298kJ/mol$). This enormous increase indicates that the second electron is removed from a highly stable, noble gas core configuration. Therefore, element C belongs to Group 1 and has exactly one valence electron ($n{s}^1$). Since C is a 2ⁿᵈ-period element, it is identified as Lithium (Li) ($1s^{2}2s^1$). The atomic number of Lithium is 3, so the number of protons in C is 3.