![Page 1: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/1.jpg)
Valence Electrons The electrons responsible for the
chemical properties of atoms are those in the outer energy level.
Valence electrons - The electrons in the outer energy level or shell
–the highest occupied energy level Inner electrons -those in the energy
levels below.
![Page 2: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/2.jpg)
Keeping Track of Electrons Atoms in the same column...
–Have the same outer electron configuration.
–Have the same valence electrons. Easily found: same as the main group
number on the periodic table. Group 2: Be, Mg, Ca, Sr, Ba.
–2 valence electrons
![Page 3: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/3.jpg)
Electron Dot diagrams A way of keeping track of
valence electrons. How to write them? Write the symbol. Put one dot for each
valence electron Don’t pair up until they
have to.
X
![Page 4: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/4.jpg)
The Electron Dot diagram for Nitrogen
Nitrogen has 5 valence electrons.
First we write the symbol.
NThen add 1 electron at a time to each side.Until they are forced to pair up.
![Page 5: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/5.jpg)
Electron Configurations for Cations
Metals lose electrons to attain noble gas configuration (full outer shell).
They make positive ions (cations) If we look at the electron configuration,
it makes sense to lose electrons: Na 2,8,1 1 valence electron Na+ 2,8 noble gas configuration
![Page 6: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/6.jpg)
Electron Dots For Cations Metals will have few valence
electrons (usually 3 or less)
Ca
![Page 7: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/7.jpg)
Electron Dots For Cations Metals will have few valence electrons These will come off
Ca
![Page 8: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/8.jpg)
Electron Dots For Cations Metals will have few valence electrons These will come off Forming positive ions
Ca2+noble gas configuration
![Page 9: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/9.jpg)
Electron Configurations for Anions
Nonmetals gain electrons to attain noble gas configuration.
They make negative ions (anions) Halide ions- ions from chlorine or other
halogens that gain electrons S (2,8,6) - 6 valence electrons S2- (2,8,8) - a noble gas configuration.
![Page 10: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/10.jpg)
Electron Dots For Anions Nonmetals will have many valence
electrons (usually 5 or more) They will gain electrons to fill outer shell.
P P3-
![Page 11: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/11.jpg)
Stable Electron Configurations All atoms react to achieve noble gas
configuration. Noble gases have 8 outer shell
(valence) electrons. This is also called the octet rule.
Ar
![Page 12: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/12.jpg)
Ionic BondingBetween metals and non-metalsTransfer of electronsFull outer shellsOppositely charged ions createdIons held to one another by
electrostatic attractionGiant structure formed
![Page 13: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/13.jpg)
Ionic Bonds
Characteristics of ionic compounds Usually soluble in water Electrical conductors when molten
and when in aqueous solution. High m.p. Brittle, hard crystals
![Page 14: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/14.jpg)
Ionic Bonding Anions and cations are held
together by opposite charges. Ionic compounds are called salts. Simplest ratio is called the formula
unit. The bond is formed through the
transfer of electrons. Electrons are transferred to achieve
noble gas configuration.
![Page 15: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/15.jpg)
Ionic Bonding
Na Cl
![Page 16: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/16.jpg)
Ionic Bonding
Na+ Cl-
![Page 17: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/17.jpg)
Ionic Bonding All the electrons must be accounted for
Ca P
![Page 18: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/18.jpg)
Ionic Bonding
Ca P
![Page 19: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/19.jpg)
Ionic Bonding
Ca2+ P
![Page 20: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/20.jpg)
Ionic Bonding
Ca2+ P
Ca
![Page 21: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/21.jpg)
Ionic Bonding
Ca2+ P 3-
Ca
![Page 22: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/22.jpg)
Ionic Bonding
Ca2+ P 3-
Ca P
![Page 23: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/23.jpg)
Ionic Bonding
Ca2+ P 3-
Ca2+ P
![Page 24: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/24.jpg)
Ionic Bonding
Ca2+ P 3-
Ca2+ P
Ca
![Page 25: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/25.jpg)
Ionic Bonding
Ca2+ P 3-
Ca2+ P
Ca
![Page 26: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/26.jpg)
Ionic Bonding
Ca2+ P 3-
Ca2+P
3-
Ca2+
![Page 27: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/27.jpg)
Ionic Bonding
= Ca3P2Formula Unit
Calcium Phosphide
![Page 28: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/28.jpg)
Classwork problems (a)Show the bonding between the following
1. Magnesium and Oxygen
2. Potassium and Chlorine
3. Calcium and Fluorine
4. Lithium and Nitrogen
5. Aluminium and Fluorine
![Page 29: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/29.jpg)
Properties of Ionic Compounds Crystalline structure, usually solids A regular repeating arrangement of
ions in the solid Ions are strongly bonded together. Structure is rigid. High melting points Electrical conductors when melted Electrical conductors in solution
![Page 30: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/30.jpg)
Crystalline structure
![Page 31: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/31.jpg)
Conducting electricity Conducting electricity is allowing charges to
move. In a solid, the ions have charges but are locked
in place. Ionic solids are insulators. When melted, the charged ions can move
around. Melted ionic compounds conduct electricity.– To melt NaCl, it must get to about 800 ºC.
Dissolved in water (aqueous) the ions are now free to move and they conduct electricity.
![Page 32: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/32.jpg)
Ionic solids are brittle
+ - + -+- +-
+ - + -+- +-
![Page 33: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/33.jpg)
Ionic solids are brittle
+ - + -
+- +-+ - + -
+- +-
Displacing the top layer (diagram) puts ions of the same charge near one another creating strong repulsion that breaks the crystal apart.
![Page 34: Valence Electrons l The electrons responsible for the chemical properties of atoms are those in the outer energy level. l Valence electrons - The electrons](https://reader035.vdocument.in/reader035/viewer/2022062407/56649cd75503460f9499f2e1/html5/thumbnails/34.jpg)
Solubility Ionic solids are often (but not always)
soluble in water. Solubility usually (but not always)
increases with increasing temperature.