1. ELECTRON-DOT NOTATION
Depicting Electrons
ELECTRON-DOT NOTATION

2. Inner & Outer Electrons
Atoms consist of inner and outer electrons.
Only the outermost electrons in an atom can participate in bonding.
Called valence electrons.
The inner electrons do not participate in bonding.
Called non-bonding electrons.
Inner & Outer Electrons

3. Determining Number of Valence Electrons
Each group on the periodic table has a set number of valence electrons.
Group 1 elements have 1 valence electron.
Group 2 elements have 2 valence electrons.
Group 13 elements have 3 valence electrons.
Group 14 elements have 4 valence electrons.
Group 15 elements have 5 valence electrons.
Group 16 elements have 6 valence electrons.
Group 17 elements have 7 valence electrons.
Group 18 elements have 8 valence electrons.
Determining Number of Valence Electrons

4. Electron-Dot Notation
Depiction of the valence electrons of an atom.
Valence electrons are represented as dots surrounding the elemental symbol.
Fill in the blank periodic table with electron-dot notations. USE PENCIL.
Electron-Dot Notation

5. Ions Ions form when atoms gain or lose electrons.
Cations form when electrons are lost.
Positively charged.
Charge is determined by number of electrons lost.
Anions form when electrons are gained.
Negatively charged.
Charge is determined by number of electrons gained.
Octet rule: atoms will gain or lose electrons so that they have 8 valence electrons.
Ions

6. Atoms with fewer than four valence electrons will lose electrons to form cations.
A group 1 atom will lose 1 electron to form a 1+ cation.
A group 2 atom will lose 2 electrons to form a 2+ cation.
A group 13 atom will lose 3 electrons to form a 3+ cation.
Atoms with more than four valence electrons will gain electrons to form anions.
A group 15 atom will gain 3 electrons to form a 3- anion.
A group 16 atom will gain 2 electrons to form a 2- anion.
A group 17 atom will gain 1 electron to form a 1- anion.
Predicting Ions

7. Predicting Ions Certain groups do not form ions.
Group 14 (carbon group).
Group 18 (noble gases).
Predicting Ions

8. Electron-Dot Notation of Ions
Cation formation:
Remove the number of electrons appropriate for the group.
Charge is positive and equal to the number of electrons lost.
Anion formation:
Add the number of electrons appropriate for the group.
Charge is negative and equal to the number of electrons gained.
Edit your periodic table to show ion formation by removing or adding electrons to the electron-dot notation. Be sure to indicate the charge of the ions.
Electron-Dot Notation of Ions