1. The problem asks to draw the transfer of electrons in the formation of ionic compounds between given elements. 2. Ionic bonding occurs when atoms transfer electrons to achieve full outer shells, typically following the octet rule. 3. For Ca and O: Calcium (Ca) has 2 valence electrons and oxygen (O) has 6 valence electrons. 4. Calcium transfers its 2 electrons to oxygen, forming Ca$^{2+}$ and O$^{2-}$ ions. 5. For Mg and Cl: Magnesium (Mg) has 2 valence electrons and chlorine (Cl) has 7 valence electrons. 6. Magnesium transfers its 2 electrons to two chlorine atoms, forming Mg$^{2+}$ and 2 Cl$^{-}$ ions. 7. For Al and O: Aluminum (Al) has 3 valence electrons and oxygen (O) has 6 valence electrons. 8. Aluminum transfers its 3 electrons to oxygen atoms, typically forming Al$^{3+}$ and O$^{2-}$ ions, balancing charges with 2 oxygen atoms for every 3 aluminum atoms. This electron transfer creates ionic bonds by electrostatic attraction between positive and negative ions. Final answer: The electron transfer diagrams show Ca transferring 2 electrons to O, Mg transferring 2 electrons to 2 Cl atoms, and Al transferring 3 electrons to O atoms to form stable ionic compounds.