To understand the changes that occur when rubidium (Rb) reacts with bromine (Br), let's examine the general behavior of elements in these groups.
### Properties of Rubidium (Group I):
- Rubidium is an alkali metal found in Group I of the Periodic Table.
- Elements in Group I have one electron in their outermost shell.
- In forming ionic compounds, these elements tend to lose their one outer electron, resulting in a positively charged ion (a cation).
### Properties of Bromine (Group VII):
- Bromine is a halogen found in Group VII of the Periodic Table.
- Elements in Group VII have seven electrons in their outermost shell.
- These elements typically gain one electron to complete their outer shell, forming a negatively charged ion (an anion).
### Electron Change for Rubidium:
- Rubidium loses one electron to achieve a stable electronic configuration (similar to the noble gas preceding it).
- By losing one electron, rubidium forms a positively charged ion with a charge of +1, denoted as [tex]\( Rb^+ \)[/tex].
### Matching to the Correct Row:
Given the information about how rubidium behaves:
1. Electron Change: Rubidium loses an electron.
2. Formula of Ion Formed: [tex]\( Rb^+ \)[/tex].
We can now match this information to the provided table:
\begin{tabular}{|l|l|l|}
\hline & Electron change & Formula of ion formed \\
\hline A & Electron gained & [tex]\( Rb^+ \)[/tex] \\
\hline B & Electron gained & [tex]\( Rb^- \)[/tex] \\
\hline C & Electron lost & [tex]\( Rb^+ \)[/tex] \\
\hline D & Electron lost & [tex]\( Rb^- \)[/tex] \\
\hline
\end{tabular}
- Row A is incorrect because it states that rubidium gains an electron and forms [tex]\( Rb^+ \)[/tex], which contradicts the fact that gaining an electron would result in a negatively charged ion.
- Row B is incorrect because it suggests rubidium gains an electron and forms [tex]\( Rb^- \)[/tex], which is not possible for Group I elements.
- Row C is correct because it accurately reflects that rubidium loses an electron and forms [tex]\( Rb^+ \)[/tex].
- Row D is incorrect because although it correctly states that rubidium loses an electron, it incorrectly suggests that the resulting ion is [tex]\( Rb^- \)[/tex].
Thus, the correct row is:
- Row C: Electron lost & Formula of ion formed [tex]\( Rb^+ \)[/tex].
