Ch 22

Section 1

Stability in Bonding

Compound   The combination of two elements to form a new

substance.

  When elements combine to make compounds the new substance usually has different characteristics than the elements.

  Have different physical and chemical properties.

Formulas   Chemical formula- tells what elements a

compound contains and the exact number of atoms of each element in a unit of that compound.

  Subscript-means written below

  Subscript tells how many atoms are in the compound.

Formulas   Silicon dioxide has 1

silicon atom and 2 oxygen atoms.

Atomic stability   Atoms want to be

stable.

  To be stable an atom likes to have 8 electrons flying around it. (except hydrogen and helium)

 Noble gasses have 8 electrons naturally so they don’t make compounds normally.

Outer levels   Two elements that don’t have the 8 electrons that

they want can combine to form a chemical compound which gives both elements the stability they desire.

Ions   Atoms that have lost or gained electrons.

  Cation-positively charged ion

  Anion- negatively charged ion