Trends in Group 2 Properties Down the Group

Steps:

• Atomic number increases down Group 2, adding electron shells and increasing atomic size.
• Ionic radius of +2 ions increases due to more shells while maintaining charge, weakening effective nuclear attraction.
• First ionisation energy decreases as outer electrons are farther from the nucleus with increased shielding.
• Atomic radius increase correlates with decreasing ionisation energy, not increasing.

Why A is correct:

• Down Group 2, more electron shells increase the size of M²⁺ ions, as per the trend in periodic table groups.

Why the others are wrong:

• B: First ionisation energy decreases down the group due to larger atomic size and shielding effects.
• C: This statement is actually correct; first ionisation energy decreases with increasing atomic number in Group 2.
• D: As atomic radius increases down the group, first ionisation energy decreases, following the inverse relationship from atomic structure.

Final answer: A and C