What is the correct order of reactivity of group 16 elements?

O > S > Se > Te > Po

The correct answer is option 4. O > S > Se > Te > Po.

The reactivity of group 16 elements (also known as the oxygen group or chalcogens) follows a general trend where reactivity decreases down the group. Let's explore the reactivity of each element in more detail:

Oxygen (O): Oxygen is the most reactive element in group 16. It has a small atomic size and high electronegativity, making it highly reactive. Oxygen readily forms compounds with many elements, including metals, non-metals, and other non-metallic elements in the group. Common compounds of oxygen include oxides, such as carbon dioxide \((CO_2)\), water \((H_2O)\), and various metal oxides.

Sulfur (S): Sulfur is less reactive than oxygen but still more reactive than the other elements in the group. It reacts with many metals and non-metals to form sulfides and sulfur oxides. Sulfur compounds are widely used in industry, agriculture, and pharmaceuticals. For example, sulfuric acid \((H_2SO_4)\) is a highly important industrial chemical.

Selenium (Se): Selenium is less reactive than sulfur and oxygen. It reacts slowly with oxygen and other elements, forming oxides and selenides. Selenium compounds are used in various applications, including in electronics, glass making, and photovoltaic cells.

Tellurium (Te): Tellurium is less reactive than selenium and sulfur. It reacts slowly with oxygen and other elements to form oxides and tellurides. Tellurium is primarily used in metallurgy, electronics, and as an additive in certain types of glass.

Polonium (Po): Polonium is the least reactive element in group 16. It is a radioactive element with a short half-life, making it difficult to study its reactivity. Polonium is primarily known for its radioactivity and has limited practical applications.

The reactivity of group 16 elements decreases down the group, with oxygen being the most reactive and polonium being the least reactive. This trend is primarily influenced by atomic size, electronegativity, and electron configuration. Oxygen, with its small size and high electronegativity, readily forms compounds with many elements, while the reactivity decreases progressively down the group due to increasing atomic size and decreasing electronegativity.

Therefore, the correct order of reactivity for group 16 elements is: O > S > Se > Te > Po.

This order reflects the general trend observed in the reactivity of these elements.