A. They are more reactive
B. They have greater atomic radii
C. They have smaller atomic sizes
D. All
¨ The first ionization potential of alkaline earth metals is greater than alkali metals because they have smaller atomic sizes.
¨ The first ionization potential (IE1) is the energy required to remove the most loosely held electron from an atom to form a cation. Alkali metals and alkaline earth metals have low IE1 values because they have one and two valence electrons, respectively, which are held relatively weakly by the nucleus due to their large atomic size and low effective nuclear charge.
¨ However, the IE1 values of alkaline earth metals are higher than those of alkali metals because the atomic sizes of alkaline earth metals are smaller than those of alkali metals. The smaller atomic size of alkaline earth metals results in a stronger attraction between the nucleus and the valence electrons, making it more difficult to remove the valence electrons.
¨ In addition, the effective nuclear charge (Zeff) experienced by the valence electrons of alkaline earth metals is higher than that experienced by the valence electrons of alkali metals due to the increased nuclear charge and decreased atomic size. This further increases the energy required to remove the valence electrons.
Submitted by :- Jamil Ahmed