An unknown representative element has an atomic number . What is the principal quantum number (perio — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

The element with $Z=34$ is Selenium ($Se$), which has the configuration $[Ar] 3d^{10} 4s^2 4p^4$. Since the highest principal quantum number is $n=4$, it belongs to the 4th period. The element placed exactly below it in Group 16 is Tellurium ($Te$), which naturally belongs to the 5th period.