June 3 2011 - Functional Groups

Functional groups

• are organic compounds contain elements other than carbon and hydrogen.
• may be a single atom (F,Cl,Br,I) or groups of atoms ( NO2,NH2)
• generally the most reactive part of the molecule

Examples of Functional Groups

Alcohol,Halides(Halogen) or NOtro,Aldehydes,Ketones,Carboxylic Acids,Ethers,Amine,Amides,Esters

Halides and Nitro Compounds

Those compounds are named similar to that of simple hydrocarbons and can be attached to alkanes,alkenes and alkynes

The main chain name will receive one of the following prefixes if the appropriate group is attached.

*Use di-,tri-,tetra- in front for multiple groups

Halogens Nitro

F=fluoro NO2=nitro

Cl=chloro

Br=bromo

I=iodo

Properties of Halogenated Compounds

1. compounds containing F,Cl,Br and I are generally insoluble in water
2. Fluorinated hydrocarbons are unreactive.
3. Compounds containing Cl or Br are more reactive but only under drastic conditions.
4. Compounds containing I are very reactive.

Properties of Nitro Compounds (NO2)

1. Normally insoluble in water
2. Unreactive to chemical attack, except under drastic conditions
3. Tend to be explosive
4. Generally have pleasant odour

Alcohols

Alcohol contains an -OH functional group

Alcohols are named by

- using the longest carbon chain containing the OH group

- Replacing the "E" ending in the parent hydrocarbon chain with the ending "OL"

Properties of Alcohols

1. OH group in an alcohol tends to make compounds soluble in water, however, the hydrocarbon chain tends to be insoluble in water.
2. All alcohols are poisonous to some degree.

Multiple OH

- If a compound has more than one -OH group number both and add -diol(2),-triol(3) endings

Aldehydes & Ketones

Both are organic compounds that contain a carbonyl functional group.

Aldehydes

-a compound that has a double bonded oxygen at the end of a chain

-Change the parent chain ending to -al

Ketones

-a hydrocarbon chain with a double bonded oxygen that is not on either end

-add -one to the parent chain

Properties of Aldehydes & Ketones

-Both are partially soluble in water

-very reactive and easily converted or oxidized to carboxylic acids

Alkynes and Alkenes

Monday May 30, 2011

Alkynes and Alkenes

-They are the terms used relating to carbon bonds, double and triple bond

-similar naming rule to alkanes, but the ending differs depending on double/triple bond

Double Bonding (Alkenes)

-Double bonds would end in -ene rather than -ane

ex. pentane --> pentene

Triple Bonding (Alkynes)

-Triple bonds would in in -yne rather than -ane

ex. pentane --> pentyne

EXAMPLE:

1-methyl-pentane

ch2-ch2-ch2-ch2-ch3

|

ch3

2,2-dimethyl-3-hexene

CH3 H

| |

CH3-C- C = C-CH2-CH3

| | |

CH3 H H

VIDEO:

Periodic Trends

Periodic Trends

-The trend of elements in the periodic table regarding different characteristics

-A total of 6:

-metallic properties

-atomic radius

-ionization energy

-electronegativity

-reactivity

-ion charge

-metling and boiling point

-density

Metallic Properties

-The elements change from left to right arosss the table and elelements that are more metallic moves down the table

-The atom decreases aross a row from left to right and increases going down a family. When the atom is going from left to right the atomic number increases along with the nucleus

-When the atoms are going down a family the orbits are more compact and therefore the inner electons attract each other whereas the elctrons on th outer end repel each other

Reactivity

-Metals and Non-metals have and show different trends. When the metal moves down a family and right a row it is more reactive and when going up and left it is less reactive

-Non-metals are the opposite or metals, it increases or it's more reactive as an atom goes up a family

Melting/Boiling Points

-The elements from the center has the highest melting point and the Noble Gases has the lowest melting point

Ionization Energy

-Ionization Energy are energies needed to remove one elctron from an atom

-They increase as it does up and right in t he periodic table and all the noble gases have high ionization energy

-the electrons have these atoms remove eaily. When going left to right it has a higher attraction between the nucleus and the electrons whereas the outer electrons decreases as it goes down a group

Electronegativity

-how much atom wants to gain electrons

-atoms goes left to right and up they increase and decreases going down a group

-atoms with high electornegativity are strognly attracts other elctrons from another atom or it may remove an electron from a neighbor

April 26 2011 - Periodic Table

The original sketch of the periodic table by Mendeleev.

- intial copy was published in 1896 by Dmitri Mendeleev
1. The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties.
2. Elements which are similar as regards to their chemical properties have atomic weights which are either of nearly the same value (e.g., Pt, Ir, Os) or which increase regularly (e.g., K, Rb, Cs).
3. The arrangement of the elements, or of groups of elements in the order of their atomic weights, corresponds to their so-called valencies, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, Ba, C, N, O, and Sn.
4. The elements which are the most widely diffused have small atomic weights.
5. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body.
6. We must expect the discovery of many yet unknown elements–for example, elements analogous to aluminium and silicon–whose atomic weight would be between 65 and 75.
7. The atomic weight of an element may sometimes be amended by a knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between 123 and 126, and cannot be 128. (This was based on the position of tellurium between antimony and iodine whose atomic weight is 127. However Moseley later explained the position of these elements without revising the atomic weight values — see below.)
8. Certain characteristic properties of elements can be foretold from their atomic weights.


Modern periodic table

April 20 2011 - Electron Configuration

The electron configuration of an atom is a form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels.

Energy level is an amount of energy which electrons in atoms can possess ( "n"= number of energy levels)

Quantum of energy is an energy difference between 2 particular energy levels

Ground state is when electrons of atoms are in their lowest possible energy level

Excited state is when 1 or more of an atom's electrons are in energy levels other than the lowest available level

Orbital is an actual region of space occupied by an electron in particular energy level

Shell is a set of all orbitals having the same "n" value

Subshell is set of orbitals of the same type

The letters s, p, d, f refer to the four different types of orbitals

Each subshell consists of:
1: s-orbital
3: p-orbital
5: d-orbital
7: f-orbital

Due to Pauli Exclusion Principle, maximum of 2 electrons can be placed in each orbit.

For a given value of "n", different types of orbitals are possible for:

n=1 only the s- type
n=2 s- and p- types
n=3 s- , p- and d- types
n=4 s- , p- , d- and f- types.

Electron Configuration for Neutral Atoms

1. Always start with the lowest energy level.
2. Figure out how many electrons you have

3. Start at the lowest (1s) and keeping adding.
-each electron has an opposite spin designated by upward and downward arrows.

Electronic Configuration for Ions
For negative ion:
Add electrons to the unfilled subshell starting where the neutral atom left off.

For positive ion:
1. Start with neutral atom and remove electrons from outermost shell depending on the charge.
2. If there are electrons in both s and p orbital of the outermost shell, elextrons in the p-orbital are removed first.

Core Notation

the set of electrons for an atom can be divided into two subsets

-the core electrons and the outer electron.
-the core is the set of electron with the configuration of the nearest noble gas that comes before it.
-the outer electron consist of all electron outside the core electron normally take part in chemcal reactions.

Atomic Theory - April 14th

Greek philosophers believed that atomos were the smallest pieces of matter...
- Aristotle believed there were 4 elements : earth, air, fire and water

From this theory marked the beginning towards a greater understanding of matter.

There were many theories regarding this matter:

-Democritus, 300 B.C was a greek philosopher who believed that atoms were invisible particles

-Lavoisier in 1700's, he stated the first version of the law of conservation of mass and law of definite proportions

-Proust in 1799, proved that Lavoisier's law by experiments

-Dalton in 1800's defined atoms as solid and indestructible spheres based on the Law of Conservation of Mass

-J.J. Thomson in 1850's came up with the first theory atoms have either positive or negative charges which proved the existence of electrons using using a cathrode ray tube

-Rutherford in 1905, proved atoms having a positive charge, dense center with electrons outstide it and explains why electrons spun around nucleus and suggested atoms are mostly empty space

-Neils Bohr in 1885-1962, studied gaseous samples of atoms, which were made to glow by passing an electonic current through them

Bohr Diagram

Remember! Project on History of Atomic Theory

DUE: Next Tuesday

Alkanes, Branched Hydrocarbons, and Alkyl groups.

3 types of bonds :
- Single
- Double
- Triple

2 types of chain patterns :
- straight line
- circular pattern
- branched pattern

Alkanes :
- end in '-ane'
- straight/unbranched chains
- formula : CnH2n+2

Branched Hydrocarbons :
- has side branches of hydrocarbon chains

Alkyl group :
- ends in '-yl'
- alkanes which have lost one hydrogen atom


Naming Simple Alkanes.