### Correct Option: D. Electropositivity of metals decreases down the series #### Explanation of the Correct Answer: The electrochemical series is a list of elements arranged according to their standard electrode potentials. It provides insight into the relative reactivity of metals and non-metals in electrochemical reactions. 1. **Understanding Electropositivity**: - Electropositivity refers to the tendency of an atom to lose electrons and form positive ions (cations). Metals are generally electropositive, meaning they readily lose electrons. - In the electrochemical series, metals that are higher up tend to be more electropositive than those lower down. This is because the metals at the top have a greater tendency to lose electrons compared to those at the bottom. 2. **Trends in the Series**: - As you move down the electrochemical series, the electropositivity of metals decreases. This is because the metals lower in the series have higher ionization energies and are less willing to lose electrons. - For example, lithium (Li) is very electropositive and readily loses an electron to form Li⁺, while gold (Au), which is lower in the series, is much less likely to lose electrons. 3. **Conclusion**: - Therefore, option D is correct: "Electropositivity of metals decreases down the series." This reflects the trend that as you go down the series, metals become less reactive and less willing to lose electrons. #### Explanation of Incorrect Options: **A. Electropositivity of metals increase down the series**: - This statement is incorrect because, as explained, the electropositivity of metals actually decreases as you move down the series. Metals lower in the series are less likely to lose electrons compared to those higher up. **B. Electropositivity of non-metals decrease down the series**: - This statement is misleading. Non-metals are generally not characterized by electropositivity; they are more often associated with electronegativity (the ability to attract electrons). The trend for non-metals is that their electronegativity increases as you move up the series, not electropositivity. **C. Electronegativity of non-metals decrease down the series**: - This statement is also incorrect. Electronegativity, which is the tendency of an atom to attract electrons, generally increases as you move up the electrochemical series for non-metals. For example, fluorine (F) is highly electronegative, while elements like iodine (I) are less so. ### Summary of Key Points: - The electrochemical series ranks elements based on their standard electrode potentials. - Electropositivity of metals decreases down the series; higher metals are more reactive. - Non-metals are characterized by electronegativity, which increases up the series. - Understanding these trends is crucial for predicting the behavior of elements in chemical reactions.