Question

The metal of group 2 from top to bottom are Be, Mg, Ca, Sr and Ba. Which of these elements will form ions most readily and why?

Answer 1

Identifying the metal which forms ion most readily:

• As we move down the group, the atomic size of the element increases due to an increase in the number of shells.
• As the atomic size increases, the nuclear attraction on the outermost shell decreases, and hence the outer electrons are loosely held, and hence, ionization energy decreases.
• So, Barium (Ba) will form ions most readily due to the lowest ionization energy.
• The ionization of Barium can be represented as:
• $\underset{\mathrm{Barium}}{\mathrm{Ba}}\to \underset{\mathrm{Barium}\mathrm{ion}}{{\mathrm{Ba}}^{2+}}+2{\mathrm{e}}^{-}$

Hence, Barium (Ba) will form ions most readily.