Atomic Mass of Elements

The atomic mass of elements is measured with the help of unified atomic mass units. One unified atomic mass unit can be quantified as the weight of one-twelfth of the mass of a carbon-12 atom considering that it is at rest. Since protons and neutrons account for almost all of the mass of the given atom, the atomic mass of a given element is almost equal to its mass number.

What is the Atomic Mass of Elements?

The atomic mass of an element can be described as

the total mass of one atom of the given element. Its unit is called the unified atomic mass unit and is denoted by the symbol ‘u’.

Standard atomic weight is used to give the value of the mean of the atomic masses in a mixture of isotopes in a given sample of an element.

Learn more ⇒ Interactive Periodic Table

Atomic Mass of First 30 Elements

Given below is a table that lists the first 30 elements based on atomic number and their corresponding atomic mass.

1 Hydrogen 1.008
2 Helium 4.0026
3 Lithium 6.94
4 Beryllium 9.0122
5 Boron 10.81
6 Carbon 12.011
7 Nitrogen 14.007
8 Oxygen 15.999
9 Fluorine 18.998
10 Neon 20.180
11 Sodium 22.990
12 Magnesium 24.305
13 Aluminium 26.982
14 Silicon 28.085
15 Phosphorus 30.974
16 Sulfur 32.06
17 Chlorine 35.45
18 Argon 39.948
19 Potassium 39.098
20 Calcium 40.078
21 Scandium 44.956
22 Titanium 47.867
23 Vanadium 50.942
24 Chromium 51.996
25 Manganese 54.938
26 Iron 55.845
27 Cobalt 58.933
28 Nickel 58.693
29 Copper 63.546
30 Zinc 65.38

The Molecular mass of an element can be calculated by adding the atomic masses of each of its constituents. There are many ways to find the atomic mass of an element, but the easiest way is to look it up on the periodic table of elements.

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One Mole of a substance is defined as the total number of atoms in 12 grams of Carbon-12 isotope. It is denoted by ‘mol’ and is also referred to as gram molecular weight.

Frequently Asked Questions – FAQs


What is atomic mass?

Atomic mass is the average mass of the protons, neutrons, and electrons in an atom. Its unit is a unified atomic mass and is denoted by the symbol ‘u’.


What is one amu?

An Atomic mass unit or one amu is the mass unit equivalent to the one-twelfth mass of one atom of the carbon-12 isotope.


Why was carbon-12 selected as the reference element for calculating atomic mass?

Carbon-12 was chosen as a reference element for calculating atomic mass because it is naturally occurring and is present in abundance.


Is the one amu SI unit of atomic mass?

An Atomic mass unit or one amu is the physical constant accepted in the SI measurement system.


What is the full form of amu?

The atomic mass unit is the full form of amu. It is equivalent to the one-twelfth mass of one atom of the carbon-12 isotope.

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