...Moles to Volume conversion

Today we learned how to convert a mole of any gas into volume.

One mole of any gas at a specific pressure and temperature will always occupy the same volume.                  
-at 0 °C and 101.3 k Pa 1mol = 22.4L
-22.4L/mol is the molar volume at STP
(This temperature and pressure is called STP)

example:
-how many liters will 3.5mol of N occupy at STP (standard temperature and pressure)?
3.5mol x 22.4L = 78L
              1 mol
-at STP an unknown gas is found to occupy 367ml. How many moles of gas must there be?
*When doing a question like this be careful and notice that it is measured in mL instead of liters
367mL x    1L     = 0.367L
             1000mL
*first convert 367mL into liters (0.367L)
 0.367L x 1mol  = 0.0164mol
                22.4L
*now simply do the work.

...Avogadro's number (The Mole)

Today we learned about an ingenious man named Avogadro and his discovery of  the mole.

Avogadro proposed that the number of atoms in 12g of carbon is equal to a constant (this is equal to 1 mole of carbon). One mole contains 6.02e23 atoms meaning 12g of carbon contains exactly 6.02e23 atoms. The mole is a number scientists use to measure how many atoms are in a formula or single element. Basically a mole is used the same way we use the word dozen to measure how many eggs there are in a container.

example: a bottle of nitrogen contains 150g of the compound. How many moles of nitrogen are there?
150g(N) x 1mol =10.7mol
                  14g            

... Quantum Mechanics, Isotopes and Atoms, Trends on the Periodic Table, Electron Structure and Naming Compunds (Part 2)

....where was I? ......OH YEAH. 

Trends on the Periodic Table
We learned that elements that are close to each other display similar characteristics. On the periodic table, there are 7 different trends:

1. Reactivity
2. Ion Charge
3. Melting Point
4. Atomic Radium
5. Ionization Energy
6. Electronegativity
7. Density*

*Density was taught into full context during this lesson.

Reactivity:
The main information we needed to know was that metals and non-metals show different trends, the most reactive metal is Francium and the most reactive non-metal is Flourine.

Ion Charge
Elements' ion charges depend on their group (Alkali Metals, Alkali Earth Metals, Halogens, Noble Gases, etc...)

Melting Point
With the melting point, elements in the center of the table have the highest melting points and the noble gases have the lowest. Also, starting from left to right, melting point increases (until the middle on the table)
Note: Although a non-metal, Carbon has one of the highest melting points on the periodic table.

Atomic Radium
The radium increases to the top and to the right. Helium has the smallest radius and Francium has the largest radius

Ionization Energy:
Ionization energy is the energy needed to completely remove an electron from an atom. Energy increases going up to the right. Noble Gases have the highest energy, Helium is the highest, Francium is the lowest.

Electronegativity

Electronegativity refers to how much atoms want to gain electrons. The trend is the same as that of ionization energy; increasing up and to the right 

Electron Structure

Here are some things to know when drawing Electron Dot Diagrams. The nucleus is represented by the atomic symbol, for the elements, you need to determine the number of valence electrons, electrons are represented by dots around the symbol, there are four orbitals, each orbital gets 2 and each orbital gets 1 electron before getting paired up. Look to the left for an example.

When drawing Lewis Diagrams for Compounds and Ions, you need to determine the number of valence electrons for each atom and place atoms so that the valence electrons are shared to fill each orbital. To the right, you will see an example of Nitrogen Tri Chloride:

When drawing Lewis Dot Diagrams for Ionic Compounds, you first have to determine the number of valence electrons on the cation. Move these electrons to the anion. Draw square brackets ( [ ] ) around the metal and non metal. Write the charge outside of the bracket. To the right is an example of Sodium Chlorate:


Naming Compounds:
Today, the most common system is IUPAC for most chemicals
-ions
-binary ionic
-polyatomic ions
-molecular compounds
-hydrates
-acids/bases 

Chemical Formulas
Be aware of the difference between ion and compound formulas 

Multivalent Ions

Some elements can form more than 1 ion. For example, Copper has a plus 2 AND plus 1 charge. Usually the top number on the periodic table is more common. IUPAC uses roman numerals in brackets to show the charge. Classic systems were latin names of elements and suffixes -ic and -ous (larger charge and smaller charge respectively)

*Note: there are other classic names for different elements:

ferr - iron

cupp - copper 

mercur - mercury

stann - tin

aunn - gold

plumb - lead

Hydrates

Some compounds can form lattices that bod to water molecules, these crystals contain water inside them which can be released by heating. To name hydrates you: 1) write the name of the chemical formula, 2) add a prefix indicating the number of water molecules (mono-1, di-2, tri-3) and 3) add hydrate after the prefix 

 

... Quantum Mechanics, Isotopes and Atoms, Trends on the Periodic Table, Electron Structure and Naming Compunds

Before i begin, i just want to say i am really sorry that we aren't up to date with this blog. Now to put a whole lot of info into one post. 

Quantum Mechanics

Today, we learned about Quantum Mechanics. How this connects with Bohr's Theory is that the electron is a particle that must be in an orbital in the atom. What is an orbital? Its an area in 3D space where electons are presumably placed. Now there are 4 different types of orbitals. There are 'S' orbitals, 'P' orbitals, 'D' orbitals and 'F' orbitals. 'S' orbitals are sphered shape and can hold 2 electrons. 'P' orbitals are 'dumbbell shaped' and contain what are known as sub-orbitals, there are 3 of them in the 'P' orbitals and each of them can hold 2. So the maximum number of electrons a 'P' orbital can hold is 6. 'D' orbitals have 5 sub-orbitals, so the max. number the 'D' orbital can hold is 10. Lastly, the 'F' orbital has 7 sub-orbitals, so the max number of electrons the 'F' orbital can hold is 14. Refer to the image to the right for a visual view of these orbitals.

The way we can put this to use is by finding out how many and what type of electrons are certain atom has. For example, we want to know how many and what type of electrons are in a Carbon Atom. The answer would be 1s², 2s², 2p². Why? Well because the 'S' orbitals can hold 2 electrons, and since there are 2, that is already 4 electrons. But since our 'S' orbital is full, we go to the next available orbital, which is the 'P' orbital. We place 2 electrons there, and we have our answer.

Isotopes and Atoms
Before we get into Isotopes, we need to somewhat review something, the Atomic Number. Found on the top left on each 'chemical card', the Atomic Number gives us the number of protons and electrons in the atom. To find the number of Neutrons, we simply take the atomic mass (p+n) minus the atomic number (p) to get the number of neutrons (n). Now with isotopes, what they simply are are elements with the atomic number but a different mass. For example, there are 3 different types of Hydrogen Atoms: ¹H, ²H, and ³H. Take a look below for another example:

 

Mass Spectrometers

These are used to determine the adundance and mass of the isotopes of elements

Formula	Mass	Protons	Neutrons
90Zr	90	40	50
91Zr	91	40	51
92Zr	92	40	52
94Zr	94	40	54
96Zr	96	40	56

This post will continue to part 2.