Ch. 22 Chemical Bonds
, What is a Chemical Formula?
• When elements combine to form compounds a
chemical reaction occurs creating a new compound with
properties that are different from the original elements.
• When a new compound is formed it has a new chemical
formula. A chemical formula tells what elements a
compound contains and the exact number of atoms of
each element in a unit of that compound.
• Example: 2Na + Cl2 2NaCl
, Why do atoms form compounds?
• The electric forces between electrons and
protons (which are oppositely charged) hold
atoms and molecules together which cause
compounds to form.
• But, not all atoms form compounds readily.
Noble gases already have all the electrons they
need! In other words, their outer energy level is
completely filled.
• When an atoms outer energy level is filled, they
are considered chemically stable.
, What is a Chemical Formula?
• When elements combine to form compounds a
chemical reaction occurs creating a new compound with
properties that are different from the original elements.
• When a new compound is formed it has a new chemical
formula. A chemical formula tells what elements a
compound contains and the exact number of atoms of
each element in a unit of that compound.
• Example: 2Na + Cl2 2NaCl
, Why do atoms form compounds?
• The electric forces between electrons and
protons (which are oppositely charged) hold
atoms and molecules together which cause
compounds to form.
• But, not all atoms form compounds readily.
Noble gases already have all the electrons they
need! In other words, their outer energy level is
completely filled.
• When an atoms outer energy level is filled, they
are considered chemically stable.
