Question

elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?
○ how many protons and neutrons they have
○ which chemical properties they have
○ how many total electrons they have
○ which period they are most often found in

Explanation:

• For "how many protons and neutrons they have": Alkaline earth metals (group 2) have different numbers of protons (atomic number varies) and neutrons (mass number - atomic number varies), so this is incorrect.
• For "which chemical properties they have": Elements in the same group have the same number of valence electrons, which leads to similar chemical properties. Alkaline earth metals have 2 valence electrons, so their chemical properties (like reactivity, forming compounds) are similar.
• For "how many total electrons they have": Total electrons equal atomic number, and group 2 elements have different atomic numbers (e.g., Be has 4, Mg has 12), so total electrons differ, making this incorrect.
• For "which period they are most often found in": Periods are horizontal rows, and group 2 elements are in different periods (Be in period 2, Mg in period 3, etc.), so this is incorrect.

Answer:

B. which chemical properties they have