Final answer:
In Group IIA, the atomic radius increases, ionization energy decreases, and reactivity increases as one moves down the group while melting and boiling points decrease.
Step-by-step explanation:
The trends of the metals in Group IIA, also known as the alkaline earth metals, can be summarized as follows:
- Atomic radius increases down the group.
- Ionization energy decreases down the group.
- Reactivity increases down the group.
- Melting and boiling points decrease down the group.
The increase in atomic radius down the group results from additional electron shells being added as you go down the group, which places the outer electrons further away from the nucleus. This factor, combined with the decrease in ionization energy, which indicates less energy is required to remove the outermost electron, makes metals further down Group IIA more reactive. Elements at the bottom of the group are therefore more reactive than those at the top because their outer electrons are more easily lost. Lastly, the melting and boiling points decrease down the group due to the increased distance between the positive nucleus and the negative sea of delocalized electrons, which weakens the metallic bonds.