Carbon and Its Compounds - Class 10th Science
Introduction of Carbon
Carbon is the 15th most abundant element in earth's crust and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon constitutes only 0.2% of the earth's crust. And only 0.03% of carbon compounds are present in the atmosphere in the form of carbon dioxide.
In spite of this small amount of carbon available in nature, carbon plays a very important role in our life.
Carbon is the common element found in all known forms of life. The structure of all living organisms contains carbon. Carbon remains present in a living organism even after death. Coal, petroleum, and all of their products are compounds of carbon. Carbon is an element and a non-metal.
The atomic number of carbon is 6
Some Important Facts About Carbon
Symbol of Carbon = C
Nature of carbon = Non-metal
Atomic number of carbon = 6
Number of electrons present in the atom of Carbon = 6
Number of protons present in the atom of Carbon = 6
Number of neutrons present in the atom of Carbon = 6
Number of neutrons varies in different isotopes of Carbon.
Calcualtion of Number of Neutrons in an Atom of an Element
We can calculate the number of neutrons in the element of an atom
using formula A = p + n
Where A = Atomic Mass, p = number of protons, and n = number of neutrons.
For the Carbon-12,
The Atomic Mass = 12
And, Atomic Number = 6 = Number of Electrons = Number of Protons
Thus, using formula A = p + n
⇒ 12 = 6 + n
⇒ 12 – 6 = n
⇒ 6 = n
⇒ n = 6
Thus, the number of neutrons in the Carbon Atom = 6
The Electronic Configuration of Carbon
= 2, 4 or K/2 L/4
Thus, the valence electrons of carbon = 4
Number of electrons in outermost orbit of Carbon = 4
Position of Carbon in the Periodic Table
Period = 2nd
Group Number = 6
Isotopes of Carbon
There are 15 known isotopes of Carbon.
Among the 15 only three are naturally occurring isotopes. These isotopes are 12C, 13C, and 14C
The 12C and 13C are stable isotopes of Carbon
While 14C is a radioactive isotope of Carbon
The half-life of 14C is 5730 years.
As the half-life of the 14C, an isotope of Carbon, is very short, the 14C is almost absent in ancient rocks.
The amount of 14C (an isotope of carbon) remains almost constant in a living organism.
But, the amount of 14C (an isotope of carbon) decreases periodically after the death of an organism
Because of the presence of 14C (an isotope of carbon) it is used to decide the age of a dead organism and other all objects containing organic material.
Carbon Dating or Radiocarbon Dating
There is a method called Carbon dating or Radiocarbon dating used to decide the age of ancient rocks, skeletons, and other objects containing organic material.
The Principle of Radiocarbon dating was invented by Willard Frank Libby, an American Physical Chemist in the year of 1949.
Why carbon is called tetravalent?
Since, the valency or valence electrons of a carbon atom are equal to four, thus carbon is called tetravalent.
Four valencies of carbon means, carbon can react with four atoms of the same or different elements to form compounds.