Valence Electrons Cornell Notes Valence Electrons 2 8

Valence Electrons Cornell Notes

Valence Electrons 2 -8 -8 Rule p Electrons orbit the nucleus in energy levels within the electron cloud n 1 2 n 1 8 8 3 3 7 7 4 4 2 6 5 The 1 st energy level holds 2 electrons The 2 nd and 3 rd energy levels holds 8 electrons

Valence Electrons Valence Electron p Valence electrons: electrons in the last shell or energy level of an atom. Last energy level: Level 3 1 2 1 So count the electrons in the last energy level 8 3 3 7 4 4 2 6 Valence Electrons! 6 5

Valence Electrons How many valence electrons are in this atom? 1 2 1 8 3 7 4 2 6 5 3 3 Valence Electrons

Valence Electrons How many valence electrons are in this atom? 1 2 1 3 4 2 5 5 Valence Electrons

Valence Electrons How many valence electrons are in this atom? 1 1 Valence Electrons

Valence Electrons How many valence electrons are in this atom? 1 2 Valence Electrons 2

Valence Electrons “Happy" atoms are stable atoms p Atoms are stable when their outermost energy levels (shells) are full Happy Atoms p 1 2 1 2 1 1 1 8 3 8 8 3 3 7 4 7 7 4 4 2 2 6 5 Stable

Valence Electrons Is this atom stable? 1 2 1 8 3 7 4 2 6 5 YES!

Valence Electrons Is this atom stable? 1 2 1 7 8 3 3 7 4 4 2 6 5 NO!

Valence Electrons Sad Atoms Sad atoms are not stable p When an atom's outermost shell is not complete/full it is not stable. p

Valence Electrons Is this atom unstable? 1 2 1 8 3 7 4 2 6 5 NO!

Valence Electrons Is this atom unstable? 1 2 1 7 8 3 3 7 4 4 2 6 5 YES!

Valence Electrons Sad Atoms p Atoms become stable by bonding (joining) with other elements. n n n Bonded atoms are called molecules. A covalent bond is one where atoms share electrons. An ionic bond is one where electrons are either given or taken, not shared.