Organic Chem- Functional groups

There are elements that react with hydrocarbons in organic reactions. Some of these elements are Halogens, some are Alcohols, some are Aldehydes, and some are Ketones. There numerous other types but those are the ones we are going to go through (yay!)

Let's start with Halogens and Nitro compounds

Well it is not rocket science, they include HALOGENS (fluorine, chlorine, Iodine, and bromine), and Nitro (NO2).

When they are written in a reaction, we use the prefix of the word with -o as a suffix. Example: Fluorine becomes Fluoro, Bromine becomes Bromo, etc...

An example of an organic compound with Halogens is this :

      Cl                
       |       
    CH=C-CH₂-CH₃
             |                    
            Cl                   

1,2-dichloro-1-butene

the di is used because we have 2 Chlorine atoms

Here is another example :

                                                             H   F
                                                             |    |
2HF + CH₃-CH=CH-CH₃ CH₃-C-C-CH₃ + H₂
                                                              |    |
                                                             F   H






ALCOHOLS

alcohols are the second functional group that can bond with hydro-carbons. It is evident by using the compound hydroxide (OH). And instead of using the regular suffix for the name of the compound like propANE, we will replace it with -ol; so it becomes propanOL!

The four most common alcohols are:

CH3OH methanol (methyl alcohol)

CH3CH2OH ethanol (ethyl alcohol)

CH3CH2CH2OH 1-propanol (propyl alcohol)

OH | CH3CHCH3 2-propanol (isopropyl alcohol)

ALDEHYDES & KETONES

Aldehydes and Ketones are kind of similar, especially when it comes to their properties. But they differ in the position of the oxygen double bond.

In aldehydes, the  double bond between carbon and oxygen is on one of the ends of the reaction.

Aldehyde

-->

CH3CHO (acetaldehyde)

In aldehydes, we use the same prefixes but we change the suffix. So indtead of using the standard -ane or -ene or -yne, it ends with -al. So instead of saying octane, we say octanAL!

Ketones differ only in the fact that they are present soemwhere in the middle of the reaction, not on the ends.

Ketone   --->

CH3COCH3 (acetone)

The same prefixes are used again, but with different suffixes. In this case, the word is going to end with -one. So nonane will become nonONE!!

ORGANIC CHEMISTRY

Organic Chemistry is observed all around us in our everyday life. Whether it is from your kitchen, like sugar and salt, or your everyday products like hairspray and so on.

Organic chemistry refers to the hydro-carbon bond between elements. There are millions of organic compounds out there, and each have different chemical and physical properties.

Carbon has 4 valence electrons, and it needs 4 more to fill its subshell. Therefore it forms bonds with other elements in order to be full and stable.
The 4 bonds of a carbon forms a tetrahydon, like this :






Hydrocarbons are the simplest organic compounds and they contain only carbon and hydrogen atoms.

ALKANES

Alkanes have the formula CnH2n+2 , meaning for every carbon atom, there are 4 hyrogen atoms. So if there were 2 carbon atoms, then there are 6 hydrogen atoms bonded with the carbon. Alkanes are different from others, because they are single bonds, and their suffix is -ane. So for example, C2H6, ethane, is an alkane with 2 carbons and 6 hydrogens.

Some common names include:

Methane              CH4
Ethane                 C2H6
Propane              C3H8
Butane                 C4H10
Pentane               C5H12
Hexane                C6H14
Heptane              C7H16
Octane                C8H18
Nonane               C9H20
Decane               C10H22







Properties of Alkanes

• Solid alkanes are normally soft with low melting points

• Insoluble in water

• Can exist in gases, liquids, and solids

ALKENES 

Alkenes contain at least one double bond pair of carbon. The prefix of alkenes is the same as the prefix for alkanes, except the suffix changes from -ane to -ene. So Methane will become methene and so on.Alkenes follow the formula CnH2n.
So since propane has 3 carbons, and one of them is double bonded with another, then it will have 6 hydrogens instead of 8.

Properties of Alkenes

• Can be found in gases, liquids, and solids
• Insoluble in water
• Intermolecular forces of alkenes get stronger when the size of molecules increases

Alkenes have geometric isomers, meaning the order in which the elements are arranged can differ, yet still be symmetric.




ALKYNES

They are molecules that contain at least one triple-bonded carbon pair. Just like alkanes and alkenes, we use the same prefix; but the suffix changes to -yne instead of -ane or -ene.
So if we had butane that has a triple-bond carbon in it, the name will be butyne.

Properties of Alkynes

• Soluble in water and polar solvents
• High boiling points
• Strong acidity

 

Chemical Bonding

Hello,

We are going to talk about different kinds of chemical bonding.

A few basics;

-only valence electrons are used for chemical bonding to gain a stable octet

There are 3 main types of chemical bonding:

1. Ionic Bonding: electrons are transferred
2. Polar Covalent Bonding: electrons are shared unequally
3. Non- polar covalent Bonding: electrons are shared equally

1. Ionic Bonding

In Ionic Bonding there are 2 ions:

CATions: Metal ions which tend to loose electrons

ANions: Non metal ions which tend to gain electrons.

From this, we can determine that ionic bonds very strongly bonded together which means that they have high melting temperature

Pretty simple?

Now on to polar and non polar covalent ions

Basically, non-polar covalents are the covalent bonds that we've looked at in past chemistry lessons?

And now you are thinking, how can you tell the difference?

This is the Pauling scale and this tells you the electronegativity of the atoms in the periodic table.

If the energy difference is more than 1.8 it is IONIC

If the energy difference is less than 0.5 it is NON-POLAR COVALENT

If the energy difference is between 0.5 and 1.8 it is POLAR

POLARITY

this means the electrical balance of a molecule

Non polar covalents have same electrical balance

Polar covalents have an imbalance of electrons

Few more things to know:

A dipole(no its not a mutation of a tadpole...): when one side of the molecule is positive and the other negative.



Electron Dot and Lewis Structure

Hello everyone,

We are going to talk about electron dot and Lewis diagrams.

These are ways to draw atoms like Bohr models that only shows the valence electrons.



This is Lewis structures of the atoms in the periodic table.

This is the Lewis structure of CH4.

Electron dot diagrams and Lewis Structure are very similar except for one thing.

Lewis structures represent bonds with a line and electron dot diagrams just has 2 dots to repesent bonds.

Bohr Models

Hello, everyone!

We are back and we are going to talk about Bohr Models!

But first, lets remember who Bohr is.

This is Niels Bohr. He was born in October 7, 1885 and died in November 17, 1962.

He was important in chemistry because of his Bohr models.

This is the Bohr model of hydrogen. This diagram outlines the electrons from one orbital to another and that creates an energy(photons) which is emitted from the atom.

The strength of the energy is determined by the wavelengths (as shown below).

Based on this theory, he determined that each atom has a specific colour patterns or spectra of light.

From this we can determine that electrons are in orbitals. When they absorb energy, the electrons move up orbitals and when they emit energy, they move down.

Lets remember the basics of how to draw the Bohr model.

And remember, the first orbital contains 2 electrons and 2nd and 3rd orbitals contain 8 electrons.

Thats a wrap!







PERIODIC TABLE HISTORY- Video

PERIODIC TABLE HISTORY

Jöns Jakob Berzelius	1828	Developed a table of atomic weights. Introduced letters to symbolize elements.
Johann Döbereiner	1829	Developed 'triads', groups of 3 elements with similar properties. Lithium, sodium & potassium formed a triad. Calcium, strontium & barium formed a triad. Chlorine, bromine & iodine formed a triad.	Forerunner to the notion of groups.
John Newlands	1864	The known elements (>60) were arranged in order of atomic weights and observed similarities between the first and ninth elements, the second and tenth elements etc. He proposed the 'Law of Octaves'.	Newlands' Law of Octaves identified many similarities amongst the elements, but also required similarities where none existed. He did not leave spaces for elements as yet undiscovered. Forerunner to the notion of periods.
Lothar Meyer	1869	Compiled a Periodic Table of 56 elements based on the periodicity of properties such as molar volume when arranged in order of atomic weight.	Meyer & Mendeleev produced their Periodic Tables simultaneously.
Dmitri Mendeleev	1869	Produced a table based on atomic weights but arranged 'periodically' with elements with similar properties under each other. Gaps were left for elements that were unknown at that time and their properties predicted (the elements were gallium, scandium and germanium). The order of elements was re-arranged if their properties dictated it, eg, tellerium is heavier than iodine but comes before it in the Periodic Table.	Mendeleev's Periodic Table was important because it enabled the properties of elements to be predicted by means of the 'periodic law': properties of the elements vary periodically with their atomic weights.
William Ramsay	1894	Discovered the Noble Gases.	In 1894 Ramsay removed oxygen, nitrogen, water and carbon dioxide from a sample of air and was left with a gas 19 times heavier than hydrogen, very unreactive and with an unknown emission spectrum. He called this gas Argon. In 1895 he discovered helium as a decay product of uranium and matched it to the emission spectrum of an unknown element in the sun that was discovered in 1868. (helios is the Greek for Sun). He went on to discover neon, krypton and xenon, and realised these represented a new group in the Periodic Table. Ramsay was awarded a Nobel Prize in 1904.
Henry Moseley	1913	Determined the atomic number of each of the elements. He modified the 'Periodic Law' to read that the properties of the elements vary periodically with their atomic numbers.	Moseley's modified Periodic Law puts the elements tellerium and iodine in the right order, as it does for argon and potassium, cobalt and nickel.
	1914	Predicted that there were 3 unknown elements between aluminium and gold and concluded there were only 92 elements up to and including uranium.