14.Ionic Bonding: Formation & Dot and Cross Diagrams

Based on the video, here are the notes on how ionic bonds form through electron transfer and how to represent them using dot and cross diagrams.

Electron Transfer: Ionic bonding occurs when a metal atom transfers one or more electrons to a non-metal atom.
Stability: The metal wants to lose electrons, and the non-metal wants to gain them, so that both achieve a full outer shell.
Electrostatic Attraction: Once the transfer happens, the atoms become oppositely charged ions. The strong electrostatic force of attraction between these positive and negative ions is called an ionic bond.

These diagrams are used to show the movement of electrons during bonding.

Dots vs. Crosses: Electrons from one atom are drawn as dots, and electrons from the other are drawn as crosses. This helps identify the source of each electron.
Arrows: Use an arrow to show the direction of electron transfer (usually from metal to non-metal).
Final Structure:
- Draw the ions in square brackets.
- Write the charge (e.g., 1+, 2-, etc.) in the top right corner.
- Only the outermost shells are typically required unless the question specifies otherwise.

Sodium (Na): Has 1 outer electron. It transfers this electron to Chlorine.
Chlorine (Cl): Has 7 outer electrons. It receives the 1 electron from Sodium.
Result: A Na+ ion and a Cl- ion.

Magnesium (Mg): Has 2 outer electrons it needs to lose.
Chlorine (Cl): Each Chlorine atom only needs 1 electron.
Process: Magnesium transfers one electron to each of the two Chlorine atoms.
Result: One Mg2+ ion and two Cl- ions. In the diagram, the negative ions are typically placed on either side of the positive ion to represent their attraction.