Which of the following atoms has the highest first ionization energy ?
← JEE Main 2016 · 3 Apr · Shift 1
ChemistrySingle correct+4 / -1Question 41 of 90
JEE Main 2016 · 3 Apr · Shift 1, Chemistry question 41
Answer and worked solution
Official answer: D
The alkali metals Rb, K and Na have very low first ionisation energies (one s electron outside a noble-gas core). Scandium, with a higher effective nuclear charge, is highest (about 631 kJ mol⁻¹, against 496 for Na).
Topics:Ionisation enthalpy