 Atoms bond by or electrons. TRANSFERRING SHARING  An atom’s depends on how likely it will. STABILITY REACT

 want to be therefore they want their energy filled. ATOMS OUTER-MOST STABLE LEVEL  electrons (with the exception of having electrons) make a 8 VALENCE HELIUM 2 VALENCE STABLE ATOM.

1. An atom electrons to become 2. An atom electrons to become LOSES POSITIVE GAINS NEGATIVE

 The of that FORCEATTRACTION HOLDS TWO ATOMS TOGETHER

 Elements that have react easily with whose atoms 1  Which group has 7 valence electrons?  Which group has 1 valence electron? 7 VALENCE ELECTRONS ELEMENTS GIVE UP OR SHAREELECTRON 17 – very reactive 1 – very reactive

 Usually elements have, or will their electrons.  Elements with, or will electrons VALENCE ELECTRONSLOSE 56 7 VALENCE ELECTRONS GAIN

 Have or more  Bond with by electrons.  and bond by electrons. 4VALENCE ELECTRONS METALSGAINING NONMETALS SHARING

 IONIC BONDS  COVALENT BONDS

 Atoms transfer VALENCE ELECTRONS to reach stability.  **Atoms with 5, 6 or 7 valence electrons  ** Atoms with 1, 2 or 3 valence electrons GAIN ELECTRONS TO BE STABLE LOSE ELECTRONS TO BE STABLE

 Lithium – Gives 1 Valence Electron  Fluorine – Takes 1 valence electron to become stable.  Neon – does not take or give any electrons. Neon is in group 18 and is already stable.

 When an atom or valence the becomes or electrically charged.  Ion - LOSESGAINS ELECTRONSATOM POSITIVELY NEGATIVELY An atom or group of atoms that has an electric charge (+ or - )

 When an atom an it becomes charged.  WHY DOES THIS HAPPEN? LOSESELECTRON POSITIVELY +++ POSITIVE IONS+++

 When an atom an it becomes charged.  WHY DOES THIS HAPPEN? ---NEGATIVE IONS--- GAINSELECTRON NEGATIVELY

 Atoms become charged  Transferring valence electrons cause ions to be formed  Opposite ions attract each other

 A chemical bond formed when two atoms share electrons. (Uncharged)  ***Covalent bonds usually form between and.  The of the of each holds the together when NONMETALS FORCEATTRACTION ATOMS NUCLEUS SHARING ELECTRONS

 ** A molecule is  **Remember** Atoms bond to reach (Helium 2 v.e.) which makes the  Molecular Compound: A that is of A NEUTRAL GROUP OF ATOMS JOINED BY COVALENT BONDS. COVALENTLY 8 VALENCE ELECTRONS COMPOUND STABLE COMPOUND MADEMOLECULES COVALENTLY BONDED