Atoms and Molecules

 

Matter is made up of elements

 

Atom is the smallest piece of an element.  It contains:

            Protons

            Neutrons

            Electrons

 

Terminology:

            Atomic number

            Mass number

            Isotope

 

Forming chemical bonds -- 7 simple rules to understanding chemical reactivity

Not all atoms are equally reactive (that is, elements differ)

Reactivity is based on the arrangement of electrons (not MP, BP)

Only valence electrons matter (valence electrons are in the outer orbital)

Atoms whose outer shell is full are non-reactive

In larger orbitals, 8 valence electrons is non-reactive

Chemical reactions lead to all atoms having stable electron configurations

Atoms form chemical bonds by gaining, losing, or sharing electrons