Based on the Lewis or electron dot representation of the two atoms, predict the ratio of calcium to fluorine in the compound. ca. A. 31 B. 1:2 C11 D. 21

To determine the ratio of calcium to fluorine in a compound using Lewis dot structures, we need to consider the valence electrons and how these atoms achieve stable electron configurations.<br /><br />1. **Calcium (Ca):** Calcium is in Group 2 of the periodic table, which means it has 2 valence electrons. In order to achieve a stable electron configuration similar to the noble gases, calcium tends to lose its 2 valence electrons, forming a \( \text{Ca}^{2+} \) ion.<br /><br />2. **Fluorine (F):** Fluorine is in Group 17 of the periodic table, meaning it has 7 valence electrons. To achieve a stable electron configuration, fluorine tends to gain 1 electron, forming a \( \text{F}^{-} \) ion.<br /><br />When calcium and fluorine react to form a compound, calcium will lose its 2 electrons, and each fluorine atom will gain 1 electron. Therefore, one calcium atom can provide electrons to two fluorine atoms. This results in the formation of calcium fluoride with the chemical formula \( \text{CaF}_2 \).<br /><br />Thus, the ratio of calcium to fluorine in the compound is 1:2.