VALENCE ELECTRONS 3.26.13
MODELING ELECTRON CLOUDS
VALENCE SHELL AND VALENCE ELECTRONS
- The electron cloud is broken up into layers.
- The layers of the electron cloud are called energy levels, or energy shells.
- There is up to 7 energy levels for an atom.
- In an atom, energy level 1 can have 2 neutrons. The 2-7th can have up to 8, with some exceptions.
VALENCE SHELL AND VALENCE ELECTRONS
- The number of electrons in the outer layer controls how or if atoms react with other atoms.
- A valence shell is the outermost energy level or shell of an atom.
- Valence electrons are the amount of electrons on that last energy level.
REACTIVITY
- Atoms tend to combine so their valence shells are full.
- 1. If a neutral atom's valence shell is full, then the atom will not react with other atoms.
- 2. If a neutral atom's valence shell has space available, then the atom will react with other atoms based on the number of electrons found in the valence shell.
- Some atoms lose electrons and become positive ions.
- Some atoms gain electrons and become negative ions.
- Some atoms share electrons within a chemical reaction.