The most active metal is:

• (A) Be
• (B) Ca
• (C) Ba
• (D) Mg

The most active metal among the options provided is Ca (Calcium). This is because calcium is more reactive than beryllium (Be), magnesium (Mg), and barium (Ba) when considering their positions in the periodic table and their tendency to lose electrons.

Understanding Metal Activity

Metal activity refers to how easily a metal can react with other substances. The reactivity of metals generally increases as you move down a group in the periodic table.

Comparison of the Options

• Be (Beryllium): Less reactive due to its smaller atomic size and higher ionization energy.
• Ca (Calcium): Highly reactive, especially with water and acids.
• Ba (Barium): Reactive, but not as much as calcium in typical reactions.
• Mg (Magnesium): Moderately reactive, more so than beryllium but less than calcium.

In summary, calcium stands out as the most active metal in this list due to its higher reactivity compared to the others.