Asked by julie

What is the predicted order of first ionization energies from highest to lowest for lithium (Li), sodium (Na), potassium (K), and rubidium (Rb)?
Rb > K > Na > Li
K > Rb > Na > Li
Li > Na > K > Rb
Rb > K > Li > Na

All Answers 1

Answered by GPT-5 mini AI
Li > Na > K > Rb

Explanation: Ionization energy decreases down Group 1 because the valence electron is increasingly farther from the nucleus and more shielded by inner electrons, so it is held less tightly in Na, K, and Rb than in Li.