Download Powerpoint Lesson Ions and Periodic Table

Chapter 3
IONS and The Periodic Table
Ions

Atoms acquire a charge by gaining or losing electrons
– not protons!!

Ion Charge = # protons – # electrons

ions with a + charge are called cations
– more protons than electrons
– form by losing electrons

ions with a – charge are called anions
– more electrons than protons
– form by gaining electrons
EXIT
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Atomic Structures of Ions

Metals form cations

For each positive charge the ion has 1 less electron than the
neutral atom
– Na atom = 11 p+ and 11 e-, Na+ ion = 11 p+ and 10 e– Ca atom = 20 p+ and 20 e-, Ca2+ ion = 20 p+ and 18 e-

Cations are named the same as the metal
sodium
Na  Na+ + 1ecalcium
Ca  Ca2+ + 2e-

sodium ion
calcium ion
The charge on a cation can be determined from the Group
number on the Periodic Table
– Group 1A  +1, Group 2A  +2, (Al, Ga, In)  +3
EXIT
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Atomic Structures of Ions

Nonmetals form anions

For each negative charge the ion has 1 more electron than the
neutral atom
– F = 9 e-, F- = 10 e– P = 15 e-, P3- = 18 e-

Anions are named by changing the ending of the name to -ide
fluorine
F + 1e-  Ffluoride ion
oxygen
O + 2e-  O2oxide ion

The charge on an anion can be determined from the Group
number on the Periodic Table
– Group 7A  -1, Group 6A  -2
EXIT
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Common Ions
1
2
18
13
Li+1 Be+2
Na+1 Mg+2
K+1 Ca+2
Rb+1 Sr+2
Al+3
Zn+2 Ga+3
Ag+1 Cd+2 In+3
15 16 17
N-3 O-2
F-1
P-3 S-2
Cl-1
As-3 Se-2 Br-1
Te-2 I-1
Cs+1 Ba+2
EXIT
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