Question

correctly name the compound $\ce{rb_{2}o}$.

a dirubidium oxygen

b dirubidium oxide

c rubidium oxide

d rubidium oxygen

Explanation:

To name the ionic compound \( \text{Rb}_2\text{O} \), we first identify the ions. Rubidium (Rb) is an alkali metal and forms \( \text{Rb}^+ \) ions. Oxygen (O) forms \( \text{O}^{2-} \) ions (oxide ion). For ionic compounds, we name the cation first (using the element name) and then the anion (using the -ide suffix for non - metal anions). The formula \( \text{Rb}_2\text{O} \) has two \( \text{Rb}^+ \) ions to balance one \( \text{O}^{2-} \) ion. The cation is rubidium (we don't use a prefix for the cation in this case as it's a metal with a fixed charge), and the anion is oxide. So the name is rubidium oxide. Option a and b use the incorrect prefix "di - " for rubidium (since rubidium has a fixed charge in its ionic compounds, we don't use prefixes to indicate the number of cations), and option d uses "oxygen" instead of the correct anion name "oxide".

Answer:

c. rubidium oxide