Ionic Bonds

Chemical bonding: The process of taking elements and atoms and combining them to form compounds or molecules.
- Energy exchange: Chemical bonds involve an exchange of energy between atoms.
- Magnetic analogy: Can be compared to magnets attracting to each other due to their magnetic fields created by electron spin.

Molecule: Defined as two or more elements joined together. Examples include:
- Oxygen (O$_2$) is a molecule.
- Carbon dioxide (CO$_2$) is both a molecule and a compound.
- Silver (Ag) is an atom and not a molecule as it consists of a single element.
Compound: Composed of two or more different elements held together by energy.
- Key distinction: A compound must consist of different elements. For example:
- Carbon dioxide (CO$_2$) is both a molecule and a compound.
- Oxygen (O$_2$) is only a molecule, not a compound.

Chemical Bond: An interaction between atoms that involves energy levels and valence electrons, which are crucial in the bonding process.
Valence Electrons: Electrons located in the outermost orbital of an atom responsible for chemical bonding.
- Atoms strive to achieve stable electron arrangements, often resembling noble gases.

Lithium (Li):
- Atomic number: 3 (1 valence electron).
- Located in group 1 of the periodic table.
Chlorine (Cl):
- Atomic number: 17 (7 valence electrons).
- Aims to gain one electron.
Ionic Bond:
- Formed when electrons are transferred from one atom to another, creating charged ions (cations and anions).
- Example of formation:
  - Lithium gives up its one electron to chlorine.
  - Lithium becomes a +1 ion, and chlorine becomes a -1 ion, resulting in a neutral compound (LiCl).
Ion: A positively or negatively charged atom.
- Lithium (Li) becomes Li$^+$ and chlorine (Cl) becomes Cl$^-$.

Octet Rule: Atoms desire to have 8 electrons in their valence shell for stability (except for some elements like lithium that require only 2).
- Noble gases are stable with 8 valence electrons, making them less reactive.
- Personification: Atoms can be thought of as having desires similar to living beings in chemistry for stability and balance.

Metals: Located on the left-hand side of the periodic table, they tend to lose valence electrons easily, forming cations (positively charged ions).
- Example: Sodium (Na) becomes Na$^+$ upon losing one valence electron.
- Common Cation Forms: Elements in group 1 become +1, group 2 become +2, etc.
Nonmetals: Found on the right-hand side, these elements tend to gain valence electrons, forming anions (negatively charged ions).
- Example: Halogens like fluorine (F) gain electrons to become F$^-$.

Cations: Formed by losing electrons.
- Example: Aluminum (Al) forms Al$^{3+}$ by losing three electrons.
Anions: Formed by gaining electrons.
- Example: Fluorine gains one electron to form F$^-$.
Charge Balance: In neutral compounds, the total positive charge must equal the total negative charge (e.g., Li$^+$ and Cl$^-$ combine to form LiCl which is electrically neutral).