Periodic Table & Ion Formation Science 10 Unit 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

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

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+

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-)

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

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

Assignment In Class: Periodic Table Scavenger Hunt Homework: Workbook pages 60-61 (leave Q4 on P61 until after next class)