Properties and lewis dots notes

1. Properties and lewis dots notes Please select the “slide show” tab and “play from beginning”

2. Properties of different bonds Ionic An attractive force between two oppositely charged ions, formed when a metal and a nonmetal bond Covalent Sharing of electrons between atoms, forms when two nonmetals bond Can be polar or nonpolar Polar – has an uneven electronegative charge Non-polar – has an even charge

3. Properties of each type of compound • Covalent compounds • Low melting point • Does not conduct • brittle • Ionic compounds • High melting point • Conducts when melted or dissolved • Form crystals • Soluble in water

4. Draw the lewis dot diagrams • CCl4 • First write out the symbol for each element and put a dot for each outer electron. There can be a total of 8 dots, with up to 2 on each side. You can tell the number of outer electrons by using the periodic table. Electrons prefer not to pair up on the same side if they can help it. • You need to rearrange the elements so they all can share and have 8 electrons. Except for Hydrogen, he only wants to share to have 2. • Draw lines to connect the single • electrons to each other

5. Each Clhas 7 outer electrons of it’s own and is sharing one with C to add up to 8 • The C has 4 outer electrons of it’s own and is sharing one from each of the Cl. This adds up to 8 as well. • ☺☺☺ This makes everybody happy ☺☺☺

6. Draw the Lewis dot diagram • b. N2 • Write out the elements and draw the outer electrons in. Remember they don’t sit together on an element unless they have to. • Each Nitrogen has 5 electrons, which means they will want to share 3 to add up to 8.

7. Draw the lewis dot diagram • C2H4 • Write the elements and draw in the outer electrons. • Hydrogen only has one outer electron and only wants to share one more to have 2 • Use lines to connect the dots and see if you can make all of the elements happy. C wants 8, H wants 2

8. Repulsive force… • Unshared pairs have a greater repulsive force and push the shared pairs away. This is why water is polar. • You would think H2O would look like this: • The unshared electrons actually push away the shared pairs, making H2O shaped like this: • This creates a negative charge on the oxygen and a positive charge by the hydrogens. These uneven charges make the molecule polar.

9. Shapes of molecules • Trigonal Pyramidal • 3 shared pairs, 1 unshared pairs • Lewis dot diagram looks like this: • 3D model: 3D drawing: • Note: A “wedge” shaped line is coming out of the page • A dotted line is going into the page

10. Shapes of molecules • Bent • 2 shared pairs, 1 or 2 unshared pairs • Lewis dot diagram would look like this: • or • A 3D diagram would look like this:

11. Shapes of molecules • Tetrahedral • 4 shared pairs, no unshared pairs • The Lewis dot diagram looks like this: • The 3D molecule would look like this: • The 3D Lewis dot diagram would look like this:

12. Shapes of Molecules • Trigonal planar • 3 shared pairs, no unshared pairs. • A double bond counts as one shared pair • A Lewis dot diagram would look like this: • A 3D diagram would look like this:

13. Shapes of Molecules • Linear • 2 shared pairs, double and triple bonds count as one shared pair, no unshared pairs • Lewis dot diagram looks like this: 3D diagram looks like this: