The successive ionization potentials of an element are measured as , and . What is the exact number — Periodic Table and Periodicity Chemistry Question
Question
The successive ionization potentials of an element $M$ are measured as $8.3, 25.1, 37.9, 259.3$, and $340.1 \text{ eV/atom}$. What is the exact number of halogen atoms ($X$) bonded to $M$ in the most stable molecular formula of its halide ($MX_n$)?
Answer: 3
💡 Solution & Explanation
There is a massive, sudden jump in ionization energy between $IE_3$ ($37.9 \text{ eV}$) and $IE_4$ ($259.3 \text{ eV}$). This indicates that the 4th electron is being removed from a stable, fully-filled inner noble gas core. Therefore, element $M$ has exactly 3 valence electrons (Group 13 element). Its stable oxidation state is $+3$, so it will form a trihalide with the formula $MX_3$.
💬Ask on WhatsApp →
Still have doubts about this question?
Send it to our AI chemistry tutor on WhatsApp — gets answered in minutes