1. Which sequence correctly places the elements in order of increasing ionization energy?
A) H – Li – Na - K
B)I Br – Cl F
C) O - S - Se - Te
D) H - Be - Al – Ga

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

The answer is nitrogen-containing bases