1. Periodic Table & Ion Formation
Science 10 Unit 2

2. Periodic Table: Period 1 Period 2 Period 3 Period 4 Period 5 Period 6
Elements are organized by atomic number (# of protons)
Left  Right across each row.
Each row is called a period.
Period # = # of electron shells in an atom.
Period 1
Period 2
Period 3
Period 4
Period 5
Period 6
Period 7

3. Each column is called a group or family.
Elements in the same group have similar chemical properties.
Group 1:
Alkali Metals
Very reactive metals 2:
Alkaline Earth Metals
Somewhat reactive metals
3-12:
Transition Metals
17:
Halogens
Very reactive non-metals
18:
Noble Gases
Very unreactive gaseous non-metals
Last digit of group # equals the # of valence electrons in the atom. (coloured groups only, not including transition elements) 1 17 18 2 13 14 15 16 3 4 5 6 7 8 9 10 11 12

4. Ions All atoms want to have a full outer electron shell (valence).
Atoms will gain or lose electrons to achieve a full valence.
When atoms gain or lose electrons, they become electrically charged.
The number of protons (+) is no longer equal to the number of electrons (-).
E.g.: Sodium now has 11 protons (+) and only 10 electrons (-) giving it an overall charge of 1+

5. Ions
Metals tend to lose electrons to become postive ions (cations). +
1e- lost
Lithium
Lithium ion (Li+)
Non-metals tend to gain electrons to become negative ions (anions). -2
2e- gained
Oxygen
Oxygen ion (O2-)

6. Ions
Note: to tell at a glance what kind of ion an element will form, look at the periodic table.
Group 1:
(Alkali Metals) +1 2:
(Alkaline Earth Metals) +2
13:
(Aluminum, etc.) +3
14:
(Carbon, etc.)
± 4
15:
(Nitrogen, etc.) -3
16:
(Oxygen, etc.) -2
17:
(Halogens) -1

7. Ions Some metals are multivalent (can form ions in more than one way)
i.e.: Iron can lose 2 or 3 electrons to become a 2+ or 3+ ion.
On your periodic table, the most common charge is listed on top.
Ion Charges
Most Common Ion Charges

8. Assignment In Class: Periodic Table Scavenger Hunt Homework:
Workbook pages (leave Q4 on P61 until after next class)