Question

The least reactive metal among the following is:
A) Sodium
B) Silver
C) Copper
D) Lead

Answer 1

Hint: The reactivity of the elements in the periodic table decreases as we move along the period and increases as we move along a group. Thus, metals are more reactive than nonmetals and metalloids. Metals of group 1 are very reactive.

Complete step by step answer:
The elements within the same group of the periodic table tend to exhibit similar physical and chemical properties. Metal reactivity relates to the ability to lose electrons (oxidize), form basic hydroxides, form ionic compounds with non-metals. In general, the bigger the atom, the greater the ability to lose electrons. The greater the shielding, the greater the ability to lose electrons. Therefore, metallic character increases going down the table, and decreases going across. The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive.
The metals are often divided into four classes on the basis of their activity
The Active Metals: These are the most reactive metals. They readily combine with oxygen and moisture in the atmosphere and therefore stored in an inert atmosphere, such as mineral oil. These metals are found exclusively in Groups I and II of the periodic table. E.g. Li, Na, K, Rb, Cs, Ca, Sr, Ba
The Less Active Metals: These metals are slightly less active. They don't react with water at room temperature, but they react rapidly with acids. E.g. Mg, Al, Zn, Mn
The Structural Metals: This class contains metals such as chromium, iron, tin, and lead, which react only with strong acids. E.g. Cr, Fe, Sn, Pb, Cu
The Coinage Metals: Metals in this class are so unreactive they are essentially inert at room temperature. These metals are ideal for making jewellery or coins because they do not react with the maximum of the substances they come in daily contact with. E.g. Ag, Au, Pt, Hg.

Hence, the most unreactive metals are Ag, Au, Pt, Hg.

Therefore, the correct answer is (B) Silver.

Note: Among the coinage metals, remember that Platinum (Pt) is the most unreactive metal.