Covalent Bonding

Monday, April 21, 2014

Covalent Bonding

Covalent bonding is a bond between non-metal with non-metal. It is different from Ionic bonding because, ionic bonding is  a bond between metal and  non-metal. In ionic bonding, the ions metal donate the ions to the non-metal to make a complete valence shell, while in covalent bonding the, the ions share the electrons together.

There are single bonds, double bonds and triple bonds. Double bonds can occur between 2 atoms of oxygen, and triple bonding can happen between two atoms of nitrogen. Covalent bonds doesn’t involve charged particles.

Example of covalent bonding:

Ionic bond

Ionic bond is the electrostatic attraction of positive and negative ions to each other. The metals and non-metals bond with each other to completely fill their outer shells and become stable, because before the metals and non-metals bond, the metals and non-metals have incomplete outer shells so they are unstable.

The ionic compounds are compounds that contain ions. The compounds are usually formed between metal and non-metal.

ionic bonding

Ionic Bonding

Today I learned about ionic bonding. Ionic bonding is when two elements are used to form new elements. Ions are an atom or molecule, that is the electric charge of certain compounds or elements. The goal for the electrons is to achieve an equal number of valence like the Noble Gases.

In an element there are two electrons in the first shell, and 8 electrons in the second shell until the final shell.

For example the electric charge of Oxygen:
Oxygen has a valence (last shell) of 6 electrons. So, to make the number of electrons equal like the Noble Gases, it's easier to gain electrons. So, 8-6=2. The charge of oxygen is -2.

Now, there are also other examples of element with positive charges, like sodium.
Sodium's atomic number= 11electrons
Sodium has a valence of= 3 electrons

Since sodium only has a valence of 3 electrons in the outer shell, it's easier to lose electrons, since th goal for the electrons is to achieve an equal number of electrons like the noble gases.
So, sodium has a charge of +3.

Reflection about Moles

Moles are massive numbers, they are equal to 0.012 kg of carbon-12. Moles are the unit of a substance. There are formulas used in moles. Molar mass are also related to moles as they are also part of the formula. Molar mass has the same numercial value as the Ar or Mr.

The formulas are:

"Simple Balanced Equations" Reflection

L.O: Construct a word equation and simple balanced equations

I learned how to balance equations in chemistry. It's a bit difficult at first, since I keep on getting confused what number should I put to balance the equation, because when I put  like a certain number I might get it wrong, when I see the result as not balanced.

Example:

2   AgI   +  Na2S  ----> Ag2S + 2 NaI

Ba3N2   +  6H20 -----> 3 Ba(OH)2   + 2NH3

Well, in the end I learned a trick of how to do it quick though, I learned how to balance the equation and that is by looking at the numbers that I put in each element.

Molecular mass reflection

Today I reviewed about molecular mass. Molecular mass is the sum of atomic masses in elements, to predict the mass of the compound. To find the molecular mass, first I had to find the atomic mass of the element first and that is by looking at the periodic table.The unit used in molecular mass is grams/ mole.

Example:

Chemistry Reflection, Ar and Mr

Relative Atomic Mass (Ar):
It is the average mass of an atom in an element. For example: Na=23g/mol

Relative Molecular Mass (Mr):
It is the sum of masses of elements present in a compound. The relative molecular mass can be used to predict the mass of the product of certain elements.

Ex: CO2
C=12 x 1= 12
O=16 x 2= 32
 32+12=44 g/mol

SO4
S=32 x 1= 32
O=16 x 4=64
64+32=96 g/mol

H20
H= 1 x 2=2
O=16 x 1=16
16 +2= 18 g/mol