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Carbon Mass Number

An atom is composed of different subatomic particles which are also called as fundamental particles. An element is composed of same type of atoms. Similar or different type of elements combines to form molecule. Elements are bonded with chemical bonds to form molecules. In the formation of chemical bonds, the valance electrons take part from each bonding element. Do you know what valance electrons are? Electrons, protons and neutrons are sub-atomic particles which are arranged in an atom. Protons and neutrons are placed in the nucleus and electrons are distributed in certain energy levels which are called as shell or orbits.

An atom is neutral due to equal and opposite charges of electrons and protons. Neutrons are neutral particles and contribute to the mass of atom. Electrons carry negative charge and protons carry positive charge. You must ha+ve seen the Modern Periodic Table which is based on the increasing order of atomic number of known elements. The atomic number can be defined as the total number of protons in an atom. It is represented as ‘Z’ and always comes as prefix in subscript of the chemical symbol of the element.  Therefore the chemical representation of an element is $_{z}X^{A}$.  Here ‘Z’ is atomic number, X is chemical symbol of element and A is mass number.

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How do You Get the Mass Number?

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The mass number of an atom can be defined as the sum of total number of protons and neutrons. It is represented as ‘A’ and always written as superscript in chemical symbol of the element. 

Mass Number of Atom
For example the chemical symbol of one of the isotope of hydrogen; deuterium can be written as $_{1}H^{2}$ ; in which 1 is atomic number and 2 is mass number while H is chemical symbol for hydrogen and deuterium can also be written as D. Mass number 2 indicates that there is one proton and one neutron in one deuterium atom as the atomic number of deuterium is one. In other words we can say that there is one proton and one electron in a deuterium atom with one neutron. Isotopes have different number of neutrons but the atomic number remains same. In other words; the mass number will vary for different isotopes. For example; there are three isotopes of hydrogen with mass number 1, 2 and 3. Hydrogen $_1H^1$ indicates that is one proton and no neutron in the atom whereas $_{1}H^{3}$ (tritium) contains two neutrons and one proton. 

Isotopes of Hydrogen

What is the Mass Number for Carbon?

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Carbon is one of the most abundant elements commonly found in all organic and living organisms.  The atomic number of carbon is 6 hence it contains 6 protons in its nucleus. There are 6 neutrons with 6 protons in one carbon nucleus. Therefore the mass number of carbon would be 6 + 6 = 12. 

Carbon Mass Number

Carbon 14 Mass Number

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Isotopes of an element have same atomic number but different mass number. The difference in mass number is because of different number of neutrons in isotopes. For example; there are three known isotopes of carbon; C-12, C-13 and C-14. Carbon-12 is one of the most abundant isotopes with 6 protons and 6 neutrons therefore mass number would be 12. C-13 is another isotope of carbon which contains 6 protons and 7 neutrons therefore the mass number would be 13. The radioactive isotope of carbon (radioisotope) is C-14 with half life 5570 years. Carbon-14 contains 6 protons with 8 neutrons in it. Hence the mass number of Carbon-14 is 14.

Number of Protons for Carbon

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Carbon Proton Number

Carbon is the member of 14th group of the periodic table with $2s^{2}$, $2p^{2}$ valance shell electronic configuration. The atomic number of carbon is 6 with 6 protons and 6 neutrons. The neutral carbon atom contains 6 electrons in 2 shells. First shell contains 2 electrons and 2nd shell contains 4 electrons. These 4 electrons involve in chemical bonding therefore carbon atom exhibits tetra valancy.

Atomic Mass Number of Carbon

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An atom contains electrons, protons and neutrons in it. Electrons are negatively charged particles whose negative charge is balanced by the positive charge of the protons. The mass of an atom is because of protons and neutrons as the mass of electrons is negligible. Protons and neutrons are placed at the dense center part of the atom which is called as nucleus. The atomic number of an atom indicates the total number of protons whereas mass number is the sum of both the nucleons present in the nucleus.

The chemical symbol of an element includes both the atomic number (as subscript and prefix) and mass number (as suffix and superscript). For example; $_{6}C^{14}$ is the chemical representation of carbon-14. Here 6 is the atomic number and 14 is the mass of carbon. The chemical symbol of carbon is C. Since mass number is sum of number of protons and neutrons therefore the number of neutrons in C-14 would be 14-6 = 8. There are 6 electrons in C-14 like C-12 and C-13 which are arranged in the same ways as in other two isotopes. Hence the atomic number and number of electrons remain same in all the isotope of one element only the mass number differs due to different number of neutrons in them. 

Carbon Atomic Mass Number
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