Ionic Bonding and Writing Formulas Footer Text 1/1/2019

Remember…… + + + Na Cl Na Cl Na Cl Each element gains a charge -1 When electrons transfer Na + Cl To make this Na + Cl +1 -1 Each element gains a charge positive charge = cation Negative charge = anion Footer Text 1/1/2019

Oxidative States + Na Cl These charges can also tell us the elements oxidative state Na + Cl +1 -1 Oxidative state – a super scientific way of showing how many electrons the element typically gains or loses. Footer Text 1/1/2019

Oxidative State We can tell the oxidative state of many elements by looking at the periodic table!!!! Footer Text 1/1/2019

Rules Some elements can have more than 1 oxidative state. For our purposes, this is what you must know….. Group # Oxidation # 1 +1 2 +2 3 +3 4 +4 5 -3 6 -2 7 -1 Footer Text 1/1/2019

Shortcut!! For Example: Aluminum + Chloride Oxidation numbers are good to know. They are a means to a shortcut for writing formulas, instead of drawing Lewis Dot Structures. For Example: Aluminum + Chloride Footer Text 1/1/2019

Shortcut !!!! Aluminum + Chloride First, determine the oxidation number for each element and write it at the top right corner of the element Footer Text 1/1/2019

Shortcut!!!! Aluminum + Chloride Group # Oxidation # 1 +1 2 +2 3 +3 4 +4 5 -3 6 -2 7 -1 Footer Text 1/1/2019

Shortcut!!! Al+3 + Cl-1 Al+3 + Cl-1 Now, criss cross applesauce!! Cross the numbers only, and write them at the bottom, as subscripts!! Footer Text 1/1/2019

Shortcut!!! AlCl3 Now, just for kicks, lets do it using Lewis Dot structures to see if we get the same thing Footer Text 1/1/2019

Lewis Dot Structures Cl Al + = AlCl3 + Cl + Cl Footer Text 1/1/2019