Journal

1) Lithium (Li) has the atomic number of 3. What will Li need to do to become stable? (Directions: Draw the electrons around the nucleus. What needs to occur to have the outermost layer filled?).2) Why do carbon atoms always form 4 bonds?

Observations on yesterday’s marshmallow models:

1. What do the marshmallows and toothpicks represent?

2. How many bonds do C, O, N and H always make?

3. Write at least two facts that describe the structure of the modeled molecules.

Journal

•Carbon is the basis of all organic molecules, including proteins, carb’s, etc.

•Carbon makes 4 bonds, which makes it highly versatile.

So far, we learned that:

Question to explore: Why four bonds? – To answer we will need to get back to the structure of atoms…Ingredients for life: Carbon

Ingredients for life: Carbon FILE HERE

Ions and ionic bonding:We predicted that since Chlorine needs ‘just’ one more electron to complete the octet, it will easily become an anion: Cl-. The opposite is for Na+ .

So what happens when Na and Cl meet?

Bonding across the periodic tableIons in the periodic table

- The sodium gives an electron to Chlorine, and now both become charged, with an opposite sign. They are now Ions.

- When brought together, the two opposite ions attract each other. This is an ionic bond.

Ionic Bonding:

We see from the animation, that several pairs of atoms do not form ionic bonds. But they do bond – by a covalent bond:

Each partner atom contribute 1 or more e-, and they are shared between the outer energy levels of both atoms.

Covalent Bonds:H-H

O=O*

CH4

*Double, triple bonds may occur.

Demos:

Ionic versus covalent bonding.

Story analogy: borrowing drink cans in a lecture hall…

Which is stronger – ionic or covalent?

Journal: e-Step 1: Na ClStep 2: Na+ , Cl-

Step 3: Na+ Cl-

1. Describe what is happening in the three steps above.

2. Which type of relationship is stronger – give and take, or sharing? Explain.

Bonding across the periodic table

Watch the following animation tutorial, and describe what happens when different atoms combine: ionic or not?Na-Cl

Ca-Cl

Fe-Cl

H-O

H-C

C-Cl

Mg-O

C-O

C-N

Quiz On the back of your answer sheet:1) Carbon is the major element of all organic matter. The ability of carbon to make diverse molecules stems from its tendency to form 4 covalent bonds. Based on it atomic number (6), explain why carbon forms four bonds. Draw and Write.

Ingredients for life: Carbon

Covalent Bonding: Sharing valence electrons.

Try with Hydrogen: 1e-

H HH H+ H2

Oxygen alone 6e-:

O

O

+ O

O

O=O

O2

+

Oxygen (6) and Hydrogen (1):

O HO

H

H H2O

Non-binding electronsAlso need some space!

Other types of bonds: