Lewis Diagram (Molecules)

Recently in class we have been learning structures of the Lewis Diagram.

Here's an example:


Mr. Stitt taught us a great way to draw the diagram that is easy for the class to remember.
First, here are the instructions.
1. Count up all the valence electrons.
2. Add or subtract electrons to account for any charges.
3. Put the least electronegative element in the center (except Hydrogen because it can only make one bond) and form one bound to out elements.
4. Complete octets (or duets in the case of Hydrogen around the outer atams first)
5. Create double or triple bonds to satisfy octects on the central atom.
6. If the entire compound is charged, put it in [ ] and place the charge on the outside top right corner of the bracket (ex: [ ]+)
7. Sulfur can actually acomodate 12 electrons (six bonds) and phosphorus can accomodate 10 electrons (5 bonds)

After you make your diagram, the best way to see if the lewis diagram was drawn correctly you have to check formal charges. To do this is to find one that is actually made by nature.
Ex:
(# of valence electrons on plain atom) - (# of valence electrons on atom in compound)

But you have to make sure you remember exceptions that are able to take place in the Octet Rule.
* Sulfur can have 12 electrons in it's valence (6 bonds)
* Phosphorus can have 10 electrons in its valence (5 bonds)
* Boron can have 6 electrons in it's valence (3 bonds)

These bonds are unusual but help the diagram work. When finding formal charges these bonds enable them to come out equal to nature.

Naming Compounds

There are three types of Compounds:

Type I: * Contains a metal that is in groups IA, IIA in periodic table or consist of the elements Al, Zn, Cd .   
            * Dont change the name of the cation
            * Change the ending of the anion to "-ide"
            * Never change the name of any polyatomic ions.

Type II: * Contains a metal that is NOT in the groups listed above or consist of the elements.
             * Determine charge on the cation (balance the total anion charges)
             * Don't change the name of the cation and put the charge of the cation after its name.
             * Change the ending of the anion to "-ide"
             * Never change the name of any polyatomic ions.

Type III: * No metals or polyatomic ions.
               *Name each element with prefixes
               * Don't use "mono" of first element
               * Change ending on last element to "-ide"

This are the procedures you take while making formulas.

Ionic Compounds

Do you know what an Ionic Compound is?
Well as you may know; ion- a charged ion.

There are two different charges that consists with these Ions known as; Cation and Anion.
I was taught a special way to remember with has a positive and negative charge.

(Cation)                                        (Anion)
Ca- + - ion                                    A - N -ion
a                                                          e
l                                                           g
l                                                           a
e                                                          t
d                                                          i
                                                            v
                                                            e

These charges play a large role in a method called "The Criss Cross Method."

You have your formula with charges included, then you must do the criss cross method to balance the formula.

Ex:                Na+1    N-3
     C.C.M. :  Na3      N

See how you use the charges to balance the equations?

Today's Lesson: Mystery Chemical

Today we started a lab. We placed on our safety goggles and got our equipment together and set up. The objective of this lab is by figuring out the density, solubility, freezing point, melting point, and boiling point you are then able to figure out the mystery chemical that is given to you. Today my lab group (Nikki, Taylor, and Nate) got to the point where we heated the chemical to find it's boiling point. By doing this, you have to get a beaker at least half way full of water, place it on the hot plate (which reaches, I found out today, 800 degrees) and then using a test tube ring you lower the test tube until it reaches into the beaker of water. We made calculations with our thermometer stayed in our test tube of the mystery solution throughout the whole heating process. As the temperature increased, our special thermometer recorded the data. It has a graph and data table that is organized on it. Tommorrow we are going to work hard to finish our data to find out our mystery chemical.

What I learned today is that recording simple information like boiling point, melting point, freezing point, density and solubility of a substance you are able to figure out what the chemical may be. I guess you can find out a lot of things about chemicals just by figuring physical properties.

Today's Lesson: Chapter 3

Elements make up everything in the world......



Elements are made of protons, neutrons, and electrons as you may know.
          Protons have a positive charge and are found in the nucleus. The atomic number tells how many protons and the number of protons determins the element.
          Neutrons have no charge and are also found in the nucleus.
          Protons and neutrons together equals the mass of an atom and can have different number of neutrons in the same atom.
         Electrons have a negative charge and are the same number as protons for a neutral atom.
 

The thing I found most interesting in this chapter.... Isotopes. They have different number of neutrons in the same element.
Ions are chared atoms that gain or loose electrons.

Today's Lesson: Chapter 2

Remember when I spoke of Chemical and Physical Properties? Well we learned an addition to these properties... Physical and Chemical Changes.
Physical Changes- does not change the substance (you can get it back)
Chemical Changes- changes the substances. You end up with something completely different (You can't get it back)
*INDICATORS*
-  if a new color is represented from the substance
- if a new smell is apparent
- heat lost/ absorbed
- if it gives of some sort of light
- precipitat formed
- gases evovle or given off

I have learned of mixtures and how you only can recieve distallation, manual seperation, filration, decanting,or magnetic seperation from this.
Distallation- seperation of liquids by boiling one off
Manual Seperation- when you pick out the substance with tweezers or tongs
Filtration- seperating a liquid from a powder or fine solid (an example of this is how you filter water through coffee)
Decanting- Pouring off a liquid (example: mix gravel and water together, then you can pour the water from the gravel)
Magnetic Seperation- using a magnet to seperate diamagnetic substance.

A pure substance has to be seperated through a chemical process (example: seperation of atoms). The only was to do this is through electrolysis.
Electrolysis means you use electricity to break apart a substance (example: water)

In this chapter, we have learned of elements, compounds, homogeneous mixture, and heterogeneous mixture.
Elements can be seperated physically or chemically
Compound is two or more elemnts that are bound together and can't be seperated through physical process.

   (These elements are combined in whole ratios)  
Homogeneous Mixtures and Heterogeneous Mixtures have similarities but differences as well.
They are different from Homogeneous Mixtures being the same throughout and presenting:
a Solution- liquid homogeneous mixture
a Alloy- homogeneous mixture of metals
Heterogeneous Mixtures are different throughout.

This chapter has refreshed my memory of elements, mixtures, and solutions. But also has shown me advancements of each one.

Today's Lesson: Properties

We learned about chemical and physical properties today.

Chemical Property is the characteristic that describes the ability of a substance to change to a different substance.

Some examples of this property are:
rusting (aka: oxidizing), heat, flammability, and digesting of food.
  
         (fire)                   (rusting)

Physical Property is a characteristic of a substance that can change without the substances becoming a different substance.

Some examples of this are:
smell, color, odor, volume, state (gas, liquid, or solid), boiling point, and melting point
   
           (color)                          (gas)

[ Taste is also considered a physical property but isn't used in chemistry. You don't want to place chemicals into your body what so ever, they could be very dangerous]

My Thoughts....

Chemistry has been a challenging class so far. I thought that it would be a risk for me since I'm not one for getting equations fast. I understand, but I like to make things so precise so I do understand. I took Anatomy last year and thought fantastic of it. So I decided to take the next step and do Chemistry. I learned the basics of Chemistry in middle school. I found it very interesting.
This is a new year with new advancements in knowledge. Mr. Stitt ( My Chemistry teacher) was speaking the other day of different ways of measurements. Also how, even today, scientist make mistakes with measurements and it ends very badly. He also spoke of overdose to people because of doctor's lack of measurements; many of which killed people. These truths have made me want to make sure my measurements are precise down to the last hundreth. 
Well I think Chemistry is certainly going to be an adventure! Thank goodness Mr. Stitt is there to help.