Which of the following statement(s) is/are true

Options

A. ionisation energy `prop (1)/("Screening effect")`
B. The first ionisation energies of Be and Mg are more than ionisation energies of B and Al respectively
C. Atomic and ionic radii of Niobium and Tantalum are almost same
D. Metallic and covalent radii of potassium are `2.3 A^(@)` and `2.03 A^(@)` respectively .

Answer

A, B, C, D