1. Chapter 5
Valence electrons

2. Valence electrons
Are electrons that can be lost, gained, or shared in the formation of chemical compounds ( the bonding process )
The valence electrons are the electrons in an atoms highest energy

3. Valence electrons
Valence electrons are the electrons in the highest energy levels of an elements atom
Highest energy levels are the s and p orbitals
Maximum number of valence electrons any element can have is 8

4. Valence electrons, ions, and ionic charge
When an element gains or loses electrons, an ion is formed.
An ion is an atom with a positive charge or a negative charge

5. Ions and ionic charge
An atom that loses electrons (negative charges) forms a positive ion,
the ion has more protons
+ charges in the nucleus than electrons - charges
Called a cation

6. Groups 1, 2 and 13 lose electrons
Groups 1, 2, and 13 form positive ions (cations)

7. Hydrogen H is in group 1
H has 1 valence electron
H loses one electron and forms a +1 positive ion H+
1S loses this one valence electron when bonding

8. Ions and ionic charge
Magensium, Mg is in group 2, Mg has 2 valence electrons, when Mg loses the 2 valence Mg forms a +2 ion
Mg+2
1S22S22P63S loses these 2 valence electrons

9. Boron, B in group 13, has 3 valence electrons
When B forms an ion it loses the 3 valence electrons and forms a +3 ion
B+3

10. Lithium is in group 1
Lithium has 1 valence electron in the 2nd energy level
1S22S1
Li will lose that one electron to form a +1 ion
Li+

11. Ions and ionic charges
An atom that gains electrons (negative charges) forms a negative ion
The ion has more – charges than + charges
called an anion
Groups 15, 16 and 17 gain electrons
Groups 15, 16, and 17 form negative ions (anions)

13. Valence electrons Group 1 2 13 14 15 16 17 18 # of Valence Electrons 3
Ionic
Charge +1 +2 +3 -3 -2 -1
Ion that is
Formed
Cation
Anion
s block element p block elements