Which statement best describes Group 2 metals?

Which statement best describes Group 2 metals?

• A. They form diatomic molecules in standard state.
• B. They are unreactive.
• C. They are halogens.
• D. They have low ionization energies, react with water, but less violently than Group 1.

Answer: (D)

Group 2 metals are alkaline earth metals with two valence electrons, so they form +2 ions. Their first ionization energy is relatively low compared with many elements, which lets them lose electrons and participate in reactions with water to produce metal hydroxides and hydrogen gas. However, these metals are not as reactive as the alkali metals in Group 1, so their reactions with water are less violent. As you go down the group, increasing atomic size makes ionization easier, so reactivity with water increases from Be and Mg (slow or little) to Ca, Sr, and Ba (more vigorous). This combination—low ionization energy, ability to react with water, and less violent behavior than Group 1—best fits the statement.

Group 2 metals are alkaline earth metals with two valence electrons, so they form +2 ions. Their first ionization energy is relatively low compared with many elements, which lets them lose electrons and participate in reactions with water to produce metal hydroxides and hydrogen gas. However, these metals are not as reactive as the alkali metals in Group 1, so their reactions with water are less violent. As you go down the group, increasing atomic size makes ionization easier, so reactivity with water increases from Be and Mg (slow or little) to Ca, Sr, and Ba (more vigorous). This combination—low ionization energy, ability to react with water, and less violent behavior than Group 1—best fits the statement.