Ionic Bonding Chemistry I Ionic Bonding Ionic Bonding
![Ionic Bonding Chemistry I Ionic Bonding Chemistry I](https://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-1.jpg)
Ionic Bonding Chemistry I
![Ionic Bonding Ionic Bonding](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-2.jpg)
Ionic Bonding
![Ionic Bonding and the Octet Rule • Octet Rule: Atoms will lose, gain, or Ionic Bonding and the Octet Rule • Octet Rule: Atoms will lose, gain, or](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-3.jpg)
Ionic Bonding and the Octet Rule • Octet Rule: Atoms will lose, gain, or share electrons to achieve an octet (eight valence electrons; a noble gas configuration)
![• In ionic bonding, – Metal atoms lose electrons to become like the • In ionic bonding, – Metal atoms lose electrons to become like the](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-4.jpg)
• In ionic bonding, – Metal atoms lose electrons to become like the noble gas immediately before them in the periodic table • Metals become positively charged cations Example: Mg: [Ne]3 s 2 Mg+: [Ne]3 s 1 Mg 2+: [Ne] not stable
![– Nonmetal atoms gain electrons to become like the noble gas following them on – Nonmetal atoms gain electrons to become like the noble gas following them on](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-5.jpg)
– Nonmetal atoms gain electrons to become like the noble gas following them on the periodic table • Nonmetals become negatively charged anions Example Cl: [Ne]3 s 23 p 5 Cl-: [Ne]3 s 23 p 6 = [Ar] stable
![• We can predict how many electrons an atom will lose or gain • We can predict how many electrons an atom will lose or gain](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-6.jpg)
• We can predict how many electrons an atom will lose or gain to achieve a stable, noble gas configuration, therefore, we can also predict the ionic charge
![+1 +2 varies +3 +/-4 -3 -2 -1 0 +1 +2 varies +3 +/-4 -3 -2 -1 0](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-7.jpg)
+1 +2 varies +3 +/-4 -3 -2 -1 0
![Representing the formation of an ionic bond with Lewis structures • Draw the Lewis Representing the formation of an ionic bond with Lewis structures • Draw the Lewis](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-8.jpg)
Representing the formation of an ionic bond with Lewis structures • Draw the Lewis structure for each atom in the compound • Show the transfer of valence electrons from the metal to the nonmetal with an arrow • Continue adding atoms and showing transfers of electrons until the total number of electrons lost equals the total number of electrons gained. • Rewrite the dot structures showing the ions formed – All metal ions should have no dots and have a positive charge – All nonmetal ions should have 8 dots and have a negative charge
![Examples Examples](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-9.jpg)
Examples
![Writing formulas for ionic compounds • Chemical formulas – Represent the composition of substances Writing formulas for ionic compounds • Chemical formulas – Represent the composition of substances](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-10.jpg)
Writing formulas for ionic compounds • Chemical formulas – Represent the composition of substances – Show the kinds and numbers of atoms in the smallest representative unit of a substance.
![• Formula Unit – The smallest representative unit of an ionic compound – • Formula Unit – The smallest representative unit of an ionic compound –](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-11.jpg)
• Formula Unit – The smallest representative unit of an ionic compound – The lowest whole number ratio of ions in the compound – Does not show the ionic charges
![• Sodium Chloride – Formula unit: Na. Cl – Represents the ratio of • Sodium Chloride – Formula unit: Na. Cl – Represents the ratio of](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-12.jpg)
• Sodium Chloride – Formula unit: Na. Cl – Represents the ratio of Na+ to Cl- in the 3 -dimensional structure
![• Mono-: one • Monatomic ions – Composed of only one atom which • Mono-: one • Monatomic ions – Composed of only one atom which](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-13.jpg)
• Mono-: one • Monatomic ions – Composed of only one atom which has an overall + or – charge – Examples: Na+1, O-2 • Poly-: many • Polyatomic ions – Composed of a group of atoms (many) with an overall charge – May contain subscripts (which you cannot change!) – Will usually contain at least two different elements – Examples: OH-1, CO 3 -2
![Parts of a formula Na 2 O This compound contains sodium Subscript ions of Parts of a formula Na 2 O This compound contains sodium Subscript ions of](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-14.jpg)
Parts of a formula Na 2 O This compound contains sodium Subscript ions of “ 2” means the formula unit contains “ 2” sodium ions Since there isn’t a subscript written This next to the O, that compound means there is contains only 1 oxygen in oxygen ions the formula unit
![Ca 3(PO 4)2 This compound contains calcium ions Subscript of “ 3”, the formula Ca 3(PO 4)2 This compound contains calcium ions Subscript of “ 3”, the formula](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-15.jpg)
Ca 3(PO 4)2 This compound contains calcium ions Subscript of “ 3”, the formula unit contains 3 calcium ions This compound contains a polyatomic ion phosphate, PO 4 -3 Subscript of “ 2” outside of parantheses means the formula unit contains 2 phosphate ions
![Na 2 SO 4 This compound contains the polyatomic ion sulfate, SO 4 -2 Na 2 SO 4 This compound contains the polyatomic ion sulfate, SO 4 -2](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-16.jpg)
Na 2 SO 4 This compound contains the polyatomic ion sulfate, SO 4 -2 Since there are no parantheses, the formula unit contains “ 1” sulfate ion
![Rules for writing ionic formulas • 1) The positively charged ion is written first Rules for writing ionic formulas • 1) The positively charged ion is written first](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-17.jpg)
Rules for writing ionic formulas • 1) The positively charged ion is written first
![• 2) compounds are neutral, so the algebraic sum of the charges must • 2) compounds are neutral, so the algebraic sum of the charges must](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-18.jpg)
• 2) compounds are neutral, so the algebraic sum of the charges must add to zero (the total positive charge must cancel out the total negative charge)
![• 3) never write “ 1” as a subscript • 3) never write “ 1” as a subscript](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-19.jpg)
• 3) never write “ 1” as a subscript
![• 4)Put parantheses around polyatomic ions if they need a subscript (other than • 4)Put parantheses around polyatomic ions if they need a subscript (other than](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-20.jpg)
• 4)Put parantheses around polyatomic ions if they need a subscript (other than “ 1”) •
![• 5)Reduce subscripts to simplest form • 5)Reduce subscripts to simplest form](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-21.jpg)
• 5)Reduce subscripts to simplest form
![Other things to keep in mind… • Any ionic compound will be made of Other things to keep in mind… • Any ionic compound will be made of](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-22.jpg)
Other things to keep in mind… • Any ionic compound will be made of only one type of positive ion with one type of negative ion • You must know the charge of each ion – Predict monatomic ion charges from periodic table – Look up charges of polyatomic ions in chart
![Shortcut: the crisscross method • Cross down the numerical value of each charge to Shortcut: the crisscross method • Cross down the numerical value of each charge to](http://slidetodoc.com/presentation_image_h/0af3161a052f1247f7aeac08f445aa52/image-23.jpg)
Shortcut: the crisscross method • Cross down the numerical value of each charge to become the subscript of the other ion • Make sure you consider if you have the simplest ratio; if not, reduce it
- Slides: 23