A chemical formula consists of the symbols of the constituent elements, with subscripts indicating the number of atoms of each element. It represents an electrically neutral molecule. Oxidation numbers are assigned to atoms based on whether they gain, lose, or share electrons, and help describe chemical compounds - atoms that lose electrons are assigned a positive number, while atoms that gain electrons are assigned a negative number.

1. WRITING CHEMICAL
FORMULAS

2. HOW IS A CHEMICAL FORMULA DERIVED?
 It consists of the symbols of the
constituent elements
 It indicates the number of atoms of each
elements. It is shown as a subscript.
 The molecule it represents is electrically
neutral.

3.  Oxidation number – is a tool in describing
chemical compounds.
 we refer to it as the number of electrons that an
atom gives up, accepts or shares with another
atom.
 when an atom gives up or accepts electrons, it
becomes a charged particle called an ion.

4.  For atoms that accepts electrons, we assign a
negative (-) oxidation number.
 For atoms that gives up electrons, we assign a
positive (+) oxidation number.
 For atoms that share electrons, we assign a
negative (-) oxidation number to the more
electronegative atom and a positive (+)
oxidation number to the less electronegative
atom.