Atomic Mass vs. Atomic Number
Key Differences
Comparison Chart
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Also Known As
Representation
Denoted As
Isotopes
Identification of Isotopes
Classification of Elements
Calculations
Relation
Example
Atomic Mass vs. Atomic Number
The total number of neutrons and protons that exist in the nucleus of an atom combine to make the mass of the atom known as its atomic mass. So, atomic mass is the average weight of an atom. On the flip side, the total protons numbers that are present in the atom’s nucleus known as the atomic number.
The atomic mass is also recognized as atomic weight whereas, and the atomic mass is also recognized as a proton number. The atomic mass is denoted by the letter ‘A.’ On the other hand, the atomic number denoted by the letter ‘Z.’ Atomic mass not used to differentiate between different elements. On the flip side, the atomic number used for the identification and classification of different elements. The atomic mass of an element can measure by using an atomic mass unit (amu). On the flip side, an atomic number is a number or a digit that can use to fix elements in a periodic table.
As the isotopes of an atom have the same number of protons but the different number of neutrons so, atomic mass can be used for the classification of different isotopes of an element. On the other side, all the isotopes of an element have the same atomic number so, it cannot use to classify them. For example, the atomic mass of carbon is twelve and thirteen for its two isotopes. On the flip side, its atomic number is six for all isotopes.
What is Atomic Mass?
Atomic mass is represented as the average weight of an atom and also recognized as atomic weight. An atom is composed of three subatomic particles, i.e., protons, neutrons, and electrons, as electrons are very light in weight, so the atomic mass considered as the mass of a total number of neutrons and protons present in the nucleus of an atom.
The letter ‘ A denotes the atomic mass.’ It expressed in the form of a unified atomic mass unit or ‘amu.’ One atomic mass unit is equal to 1/12 of the mass of a single C12 or carbon-12 atom with a value of 1.660 539 066 60(50) × 10−27 kg. For example, the mass of a carbon-12 atom equaled to12 amu. As electrons are very light in weight, so, the mass of a carbon-12 isotope is composed of 6 neutrons and 6 protons. The protons and neutrons have the same mass so, it said that they both have a mass equal to 1 u.
As different isotopes of an atom vary in the number of neutrons. So, they all have different atomic mass. That is why atomic mass can use to identify different isotopes of an element. But, it is not used to differentiate between different elements. The atomic mass of an element can also find out by adding the number of the neutron in its atomic number.
What is the Atomic Number?
The atomic number is the total number of protons present in the nucleus of an atom. It also recognized as a proton number. It denoted by the letter ‘Z.’ As all the isotopes of an element have the same proton number so the atomic number cannot use to differentiate between the isotopes of that element.
The atomic number is used for the identification and classification of different elements. It is a number or a digit that can use to fix elements in a periodic table. Different elements are identified according to their specific atomic number and placed in the periodic table according to it.
For example, an atom that has atomic number 12 is carbon as it has 12 protons in its nucleus. An atom with different atomic numbers will be a different number. In the periodic table, all the elements arranged according to their increasing atomic number. So, the top most element present at the upper left corner of the table is hydrogen with atomic number 1. The next one is helium with atomic number 2 and so on.
As atomic mass is the number of protons and neutrons in the nucleus of an atom so, the atomic number can also find out by deducting the number of the neutron from the atomic mass of an element.
