Of the elements: \( \mathrm{B}, \mathrm{C}, \mathrm{F}, \mathrm{Li} \), and Na . The element with the least metallic character is \( \begin{array}{l}\mathrm{B} . \\ \mathrm{F} . \\ \mathrm{Na} \text {. }\end{array} \)

Among the elements listed—**Boron (B)**, **Carbon (C)**, **Fluorine (F)**, **Lithium (Li)**, and **Sodium (Na)**—we need to identify the one with the **least metallic character**. **Metallic character** refers to how readily an element can lose electrons to form positive ions. It generally **increases**: - **Down a group** in the periodic table (as atoms become larger and the outer electrons are farther from the nucleus). - **From right to left** across a period (as elements transition from nonmetals to metals). Let's analyze the options provided: 1. **Sodium (Na):** - **Group:** 1 (Alkali metals) - **Characteristic:** Highly metallic; readily loses one electron to form Na⁺ ions. 2. **Boron (B):** - **Group:** 13 - **Characteristic:** Metalloid; exhibits both metallic and nonmetallic properties, but still retains some metallic character. 3. **Fluorine (F):** - **Group:** 17 (Halogens) - **Characteristic:** Highly nonmetallic; the most electronegative element, strongly attracts electrons and does not exhibit metallic properties. **Conclusion:** **Fluorine (F)** has the **least metallic character** among the given elements. **Answer:** F Fluorine is the element with the least metallic character among the choices.