State the number of electrons lost or gained when the following elements form ions:
e. Rb

Ion formation occurs when atoms gain or lose electrons to achieve a stable electron configuration, typically resembling that of the nearest noble gas. This process results in the creation of charged particles known as ions, which can be either cations (positively charged) or anions (negatively charged). Understanding how and why elements form ions is crucial for predicting their chemical behavior.

Rubidium (Rb) is a member of the alkali metals, which are found in Group 1 of the periodic table. These elements have one electron in their outermost shell, making them highly reactive and prone to losing that single electron to form cations with a +1 charge. Recognizing the properties of Group 1 elements helps in predicting the number of electrons they lose when forming ions.

Electron configuration describes the distribution of electrons in an atom's orbitals. For rubidium, the electron configuration is [Kr] 5s¹, indicating it has one electron in its outermost shell. When rubidium forms an ion, it loses this single valence electron, resulting in a stable electron configuration similar to that of krypton, which is essential for understanding its ionic behavior.