The actual number of each atoms present in a molecule.

​Molecular formula

The simplest-whole number-ratio of:
The atoms present in one molecule.

​Empirical formula

The empirical formula can be found by determining the mass of each element present in a sample of the compound

​Calculating EF part 1

The empirical formula can be found by determining the percentage of each element present in a sample of the compound

​Calculating EF part 2

​Calculating Molecular Formula

​Ions that contain more than one type of atoms are called, compound ions.
Here is some common compound ions and 2 metal ions that we should learn:

• Formula of Covalent Compounds:

  • You can determine the formula of a covalent compound from the number of electrons needed to achieve the stable electronic configuration of a noble gas.

• General Rules for Covalent Bonding:

  • Carbon atoms (C): Form four bonds with other atoms.

  • Hydrogen atoms (H) & Halogen atoms (e.g., F, Cl, Br, I): Form one bond.

  • Oxygen atoms (O): Form two bonds.

  • Examples:

    • Water (H₂​O): Follows these rules, with H forming one bond and O forming two bonds.

    • Methane (CH₄​): Each carbon atom bonds with four hydrogen atoms.

• Note: There are many exceptions to these rules.

• Ionic compound made from atoms that do "give n take" of e^-

• Covalent compound made from atoms that do "sharing" of e^-

• All the atoms gather and make compound to reach the stability (8e^-)

Click here to do some balancing chemical equation