Organic Chemistry: Functional Groups

Functional groups is a specific group that gives the molecule ability to react in a specific manner. And are usually in organic compound other than Carbon and Hydrogen, such as Nitrogen, Chlorine, Florine.

•Halides & Nitro Compounds

Naming rule is just attached to the Alkane and Alkene, but we have to follow the new prefixes:

F = Fluro

Br= Bromo

Cl = Chloro

NO3 = Nitro

Notes: 

We use prefixes such as di-, tri-, tetra-.... to indicate that if there is one more Compounds.

Alcohols:

1: It contains OH- and we have to name it as the lowest number as possible (start counting it from the closest way)

2: End in  - ol

3: If there is more than one OH- in it, we use prefixes such as di-, tri- to indicate it.

Aldehydes and Ketones :

The difference between aldehydes and ketones is that

1: Aldehydes contains double bond Oxygen at the end of its chain

2: Ketones contains double bond Oxygen at the MIDDLE of its chain

Aldehydes:

1: End in "-al"

 "Ketones"

1: End in "-one"

Organic Chemistry.

Organic chemistry is responsible for many everyday products of the everyday products that are used around the world, as it's composed of only organic matters like Oxygen, Hydrogen... that's naturally come from the nature in order to decrease the pollution from chemical product.

•Properties

•Low melting points

•Weak or No-electrolytes

Types of Carbon Atom Chains:

A straight-line

Circular Pattern.

Branch Pattern.

Single Bond:

Alkanes are saturated hydrocarbon which have all carbon atoms bonded by single bonds.

To name them, we have to end in "-ane" as they are Alkanes.

1: Count how many carbon is there in the LONGEST CHAIN, (usually from left to right)

2: According to the numbers of carbon, we can record the name as a symbol " Methane, Ethane...."

3: Then, use the general formula to show the Alkane.

Double Bond (Alkene):

Generally it's the same as Alkane in the naming way, but now it's Double Bond

1: End in "-ene" instead

2: Be aware the double bonding location and name it specificly according to the information has provided!

3: Draw a double line to show it's a double bond~

Triple Bond (Alkyne):

Same method of naming to Alkene, but

1: End in "-yne" instead.

2: Draw a triple line to show it's a triple bond~

Chemical Bonding

There are three types of chemical bonding:
1) Ionic bonding- the transfer between 2 atoms to form a positive ion and negative ion.
2) Non-polar covalent bonding- equal sharing of electrons
3) Polar covalent bonding- unequal sharing of electrons


The first two bondings we have already learned from previous classes, so lets started with the new bonding - Polar covalent bonding


First, we have to know the electronegativity. The difference in electronegativity will determine the electron sharing. To determine the difference, there's a formula we have to notice!: 

ENeg Diff. = lENeg1 - ENeg 2l

If ENeg Diff <0.5 it's a non polar covalent bond

If ENeg Diff > 0.5 and <1.8 it's a polar covalent bond

If ENeg Diff > 1.8 it's an ionic bond

Atoms with Higher Electronegativity
will form a PARTIAL NEGATIVE charge

•δ- (between 0 and -1)

Atoms with Lower 

Electronegativity
will form a PARTIAL
POSITIVE charge

•δ+(between 0 and +1)

INTRAmolecular forces are found within a molecule, responsible for holding the atoms of a molecule together

INTERmolecular forces are found between the molecules, responsible for the bonding between molecules

Polarity - 

 Describes a molecule's electrical balance.

According to the electronegativity from each element. By subtracting two atoms in the compound. The number as a result will tell us that what kind of bonding it is. 

For example: 

 

H2O:

H: 2.20
O:3.44


3.44-2.20= 1.24

Which mean H20 is a polar covalent bond according to the electronegativity.

Drawing Electron Dot and Lewis Diagrams

When Drawing Electron Dot and Lewis Diagrams, keep that in mind that 
-the nucleus represents the symbol
-The dot represents the electrons
-There are four orbitals in each side, each orbital can only hold 2 maximum electrons
-Each shell can only hold 8 electrons

 Electron dot diagrams help us to understand and represent the process of ion formation, and also illustrate that ionic bonds tend to produce full outer orbits of electron


Covalent Bonds:

Lets use water as an example, covalent bonds are composed by 2 non-metal atom as we've learned from previous classes. When we are doing it, remember:

- Fill each orbital into full shell
- Use line instead to replace the dot to represent the orbital is full
- Use the symbol to represent the nucleus.


Lets move on in to Ion bond.

Basically it's the same format, but please remember both elements are not SHARING electrons. So we use "+" to represents that they are joined together still, but not covalent bonds.

Trends on the Periodic Table

As we look at our periodic table all the time, it's time to learn about its Trend..... yea... I know... let's do it!

Metallic:

From left to right across the table are metallic to non-metallic, which are metal to non-metal
-As they going down, they will be more likely metal.


Atomic Radius:

The Atomic radius will decrease from the left to right,
and increase from the top to bottom.


Reactivity:

The reactivity is increasing from the middle to left and right,
- from the top to the bottom in metallic group
- from the bottom to the top in non-metallic group


Melting and Boiling Point:

The middle of the periodic table has the highest melting point,
and it'll gradually decrease from the middle to the right and left side of the periodic table.


Ionization energy: (energy needed to be removed)

 Ionization energy increases from the left bottom to the top, and from the left to the right.
Basically, Fr has the lowest ionization energy and He has the highest.


Electronegativity:

The Electronegativity increases from the left bottom to the top, and from the left to the right.
- its trend are same as ionization energy !

Valence Electron and Core Notation

Core Notation:
As we know that, writing a complete electron configuration takes a bit time and it's easy to make mistakes even we memorize it. So Core Notation can save us sometimes.
Basically it uses another element from the group "Nobel gas" before itself to replace the first part of electron configuration, and doesn't affect the electrons number of the original atom.

For example:
Electron Configuration : Al = 1s2 2s2 2p6 3s2 3p1
Core Notation: Al = [Ne] 3s2 3p1

Electron Configuration: O = 1s2 2s2 2p4
Core Notation: O = [He] 2s2 2p4

Electron Configuration : K = 1s2 2s2 2p6 3s2 3p6 4s1
Core Notation : K = [Ar] 4s1

little notes: the number of the noble gas is actually repersenting the first part of the electron configuration, so once they add up, the electrons number won't be affected as a result.

In chemistry, valence electrons are the electrons of an atom that can participate in the formation of chemical bonds with other atoms. Basically, as we know from the Bohr diagram, to be able to achieve a reaction, both reactant needed to have either Open shell or Closed shell to allow or provide electrons. And to predict the valence electrons, we used to draw a diagram, but now we have one more method from electron configuration.

Frist we have to know the role, valence electrons are not counted in the d- and f- subshells. which only refer to s- and p-.

For example:
Electron Configuration : Al = 1s2 2s2 2p6 3s2 3p1
Core Notation: Al = [Ne] 3s2 3p1

From here  [Ne] 3s2 3p1,   2 + 1 = 3
so the valence electrons are 3 from Al

Electron Configuration: O = 1s2 2s2 2p4
Core Notation: O = [He] 2s2 2p4
Valence electrons = 2 + 4 = 6

Electron Configuration : K = 1s2 2s2 2p6 3s2 3p6 4s1
Core Notation : K = [Ar] 4s1
Valence electrons = 1

Electron Configuration

As we used to draw Bohr diagram to predict the way of electrons display, it somehow takes me a bit of time to figure out the answer. But now, we're going to learn about a new method, Electron Configuration.electron configuration is the arrangement of elecrons of an atom, a molecule, or other physical structure. It concerns the way electrons can be distributed in the orbitals of the given system.

First of all, we have to know what is "Shell",
it is a value of N and Subshell is a set of orbitals of the same type, which are "s, p, d, f" that we are going to use it to show how it works.

Basically, we use these terms "s, p, d, f" to show electrons in the atom.
Let see what's the difference between them!

n=1 s-type > can fill 2 electrons
n=2 s, p type > can fill 6 electrons
n=3 s, p, d type > can fill 10 electrons
n=4 s, p, d, f type > can fill 14 electron

And now lets take a look the order of their pattern

So, the pattern is  1s2 > 2s2 > 2p6 > 3s2 > 3p6 > 4s2 > 3d10........................

And now we can do some excerises!
Oxygen, with 8 electrons.  > 1s2 2s2 2p4 : 2+2+4 = 8  (little notes, s,p,d,f doesn't have to fully fill)

Calcium, with 20 electrons. > 1s2 2s2 2p6 3s2 3p6 4s2 : 2+2+6+2+6+2 = 20

Lithium, with 3 electrons. > 1s2 2s1

Sulphur, with 16 electrons. > 1s2 2s2 2p6 3s2 3p4 : 2+2+6+2+6 = 16

Atomic Theory

Aristotle         384 BC – 332 BC

ž1 Aristotle believed an ancient Greek theory that atom

being different sizes, regular geometric shapes

and being in constant motion.

ž

•        believed that matter was made of different
•        combo of earth, air, fire and water. They represent four

•        qualities: dryness, hotness, coldness, and wetness. He didn’t really contribute much to the atoms

Democritus Contribution

•       He suggested that matters are made up of atoms, which we are still using this concept today. However, he never made any attempt to determine whether his theory was correct.

Antoine Lavoisier 1763

žproposed the Combustion Theory which was based on sound mass measurements
žHe named oxygen.
žalso proposed the Law of Conversation of Mass
which represents the beginning of modern chemistry

John Dalton       1766 - 1844

žJohn Dalton is considered the Father of Modern Atomic theory.

ždiscover the partial pressures of gases. This major advance in stoichiometry, the ratio of elements, lead to his formulation of a working theory of the atom. 

J.J. Thomson 1897

žhe showed that cathode rays are rapidly moving particles, and, by measuring their displacement by electric and magnetic fields,

he determined that these particles were nearly 2,000 times less massive than the lightest known atomic particle,
which now what we call,
electrons.

Ernest Rutherford   1909

ždiscovered that there were different types of rays; Alpha, Beta, and Gamma

ždiscovered that radioactive elements have half-life which can be used to find the age of an element and this method still be using widely today.

Niels Bohr         1885 - 1962

žBohr’s atomic theory can be described as one of the most important theories all over the world.

žThe Bohr Model is an approximation to quantum mechanics that has the virtue of being much simpler. He postulated based on quantum theory that electrons travel around an atomic nucleus in a stationary orbit. His work also led to the theory of different energy levels in atoms that is if an electron drops from a higher to a lower orbit, it must release energy.