Final answer:
The correct answer is d) melting point, which does not increase going down the group. In the alkaline earth metals group, atomic radius and metallic character increase, ionization energy decreases, but the melting point tends to decrease rather than increase.
Step-by-step explanation:
The student's question pertains to the periodic trends of alkaline earth metals in group 2 of the periodic table. Specifically, they are asking which property does NOT increase as you go down the group. The options are a) atomic radius, b) ionization energy, c) metallic character, and d) melting point.
Firstly, let's review that the atomic radius increases going down a group due to the addition of electron shells. This places the outermost electrons further away from the nucleus, leading to a larger radius.
Secondly, ionization energy, the energy required to remove an electron from an atom, generally decreases going down a group. This is because as atomic radius increases, it is easier to remove an electron that is farther away from the nucleus.
Next, metallic character, which includes properties such as conductivity and malleability, increases going down the group. This can be attributed to the increase in atomic size and the decrease in ionization energy, making it easier for atoms lower in the group to lose electrons and exhibit metallic properties.
Lastly, d) melting point does not consistently increase down the group. Contrary to properties a, b, and c, melting point tends to decrease down the alkaline earth metals group, which makes 'd) melting point' the correct answer to the student's question.