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We are going to use the Periodic Table to talk about a very important element, which is Carbon, one of the stars of modern chemistry because is present in almost every compound  around us. Carbon itself is the principal protagonist of the part of Chemistry called Organic Chemistry.


Carbon is located in Group 4A of the Periodic Table of the Elements, that means this Element will be forming compounds sharing until 4 electrons.

Carbon and Organic Chemistry are present in different kind of materials for example in paints, rubbers, oils (and all petrochemical derivates), plastics (polymers of carbon), and even in Steel forming alloys with  metals.

In live organisms Carbon is part of the skin, hair, blood (as amino acids and proteins), fats (or lipids), carbohydrates such us glucose, DNA, RNA, vitamins, and carbon dioxide, that is why is important for Pharmaceutical  and Food industries.

Carbon is also present in graphites (as in pencils) and diamonds.

Organic Chemistry is based in an element called Carbon.

How Carbon is present in all different compounds?

There are two principal characteristic of this Element, that make him different and special from other Elements:

1st) When form compounds, they share electrons, that means that they don’t take or give electrons (they do not create ionic bonding). They form covalent bondings

2nd) They are able to share until 4 electrons. Most Elements win or take less than 3 electrons.

Now, we’ll try to see How Carbon creates compounds

We know that Carbon has 4 electrons in its valence shell, these electrons are in orbitals, one electron in one orbital.

The orbitals are around Carbon, not forming 90º or 180º  among them, but 109.5º in all cases.

To complete each orbital we need 1 electron, that can be provided for an Hydrogen for example. If that is the case, one Carbon will need 4 Hydrogens, and the final molecule is Methane, CH4.

A better representation of, methane, is this. One Carbon surrounded by 4 Hydrogens at the same distance and same angle among them.

When Carbon wants to create a bigger molecule, it replaces one Hydrogen for another Carbon and complete the other bondings with other atoms, as Hydrogens or another Carbon.

For example, when in a molecule we have 3 Carbons, then we will need 8 Hydrogens, and in that case the molecule is called Propane.


The atomic radius is the distance between the nucleus to the boundary of the surrounding cloud of electrons.

Atomic radii vary in a predictable and explicable manner across the periodic table. The radius increases moving down a group due to the addition of a new energy level or shell.

The atomic radius generally decrease along each period of the table, because although more electrons are being added to atoms, they are at similar distances to the nucleus (same shell), and the increasing nuclear charge “pulls” the electron clouds inwards, making the atomic radii smaller.

The noble gases have full valence electron shells, corresponding to an electron configuration s2 p6, making them very stable and not following the exact behavior than other atoms in the neighborhood.



The Periodic Table shows us all the known elements in our planet. In the Periodic Table, the elements are presented in increasing atomic number.

Every vertical column represents a Group or Family. Groups are considered the most important method of classifying the elements, because the elements have very similar properties and exhibit a clear trend in properties down the group. Under the International naming system, the groups are numbered numerically 1 through 18 from the left most column (the alkali metals) to the right most column (the noble gases).

The rows, in the periodic table, are called Periods, there are 7 periods, the first one contains only two elements, hydrogen and helium, they are filling orbital 1s. The second and third periods have 8 elements, because involve elements with orbitals s and p and follow the octet rule. Elements in period 4 start with d orbitals (d-block), and makes the periodic table more extensive, including 10 more elements than the previous periods, these elements are the Transition Elements. When elements include orbitals f (f-block) the periodic table needs 14 more spaces, they are covered for Lanthanides and Actinides.




Atomic Number is represented by the symbol Z, and is the number of protons found in the nucleus of an atom.


The atomic Number identifies a Chemical Element, that means adding or removing protons from the nucleus of an atom creates a different element. A nucleus with 1 proton belongs to the Hydrogen, if we have 3 protons in the nucleus, that is now a Lithium atom. Other important atomic numbers belongs to Carbon, Oxygen, Gold and Uranium:  6C, 8O, 79Au, 92U.

In an atom with neutral charge, the atomic number is also equal to the number of electrons.

The Atomic Number is the upper number in the Periodic Table of the Elements.