Here's why:
* Sodium (Na) and chlorine (Cl) are both elements that want to achieve a stable electron configuration, which means having a full outer shell of electrons.
* Sodium has one electron in its outermost shell, and chlorine has seven.
* To achieve stability, sodium *loses* its outermost electron, becoming a positively charged ion (Na+).
* Chlorine *gains* this electron, becoming a negatively charged ion (Cl-).
* These oppositely charged ions are then attracted to each other, forming an ionic bond.
Sharing Electrons
* Some atoms, particularly those in the middle of the periodic table, do not have a strong tendency to gain or lose electrons.
* Instead, they achieve stability by sharing electrons with other atoms.
* This sharing creates a covalent bond, where the shared electrons are attracted to the nuclei of both atoms, holding them together.
Example:
* Oxygen (O) needs two more electrons to fill its outer shell.
* Two oxygen atoms can share two electrons each, forming a double covalent bond (O=O).
* This creates a stable molecule of oxygen gas.
In summary, while some atoms achieve stability by transferring electrons (ionic bonds), others achieve stability by sharing electrons (covalent bonds).
