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Mass
Numbers of Atoms - Definition
Definition
of Mass Numbers: All atoms have a mass number which is derived
from calculating the sum of the total number of neutrons and
protons in an atomic nucleus of a particular atom.
Mass Numbers = (Number of
Protons) + (Number of Neutrons)
Mass
Numbers - Atomic Weight
It is
necessary to establish the
atomic weight
to enable you to establish the
Mass Number.
The atomic weight or mass is, basically, a measurement of the
total number of particles in an atom's nucleus. Using the Mass
Number you will be able to calculate
the number of
Neutrons in an atom.
Mass
Numbers - How to find Mass Numbers
The mass
number is
established by rounding the atomic weight to the nearest whole
number. The
Periodic Table
with Atomic Mass will give you the atomic weight, or atomic
mass, of the elements.
The chemical
properties of an element are determined by its Atomic Number
not its Mass Number which is why atomic numbers are shown on
the Periodic table whilst Mass Numbers are not. Mass numbers
equal the total number of heavy, or massive, particles in the
nucleus. Subtracting the Atomic number from the Mass Number
equals the number of neutrons in the nucleus.
Mass Numbers = Atomic Weight
of Element, rounded to nearest whole number
Number of Neutrons = Mass
Number - Atomic Number
Mass Numbers
Mass
Numbers - The Mass Numbers of all of the elements
So, if we know the number of
protons and neutrons in an atom we can determine the mass
number. The unique chart below has been created by
www.elementalmatter.info and details all of the elements in
the Periodic table, the numbers of protons, the numbers of
neutrons and the mass numbers of atoms which relate to the
elements.
Mass numbers - Examples of Mass Numbers
The following examples
provide details of how to calculate the mass number.
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Example 1 - mass
number of Gold: The element Gold (Symbol Au) has the Atomic
Number of 79. The number of protons in atom of gold is therefore
79. Gold has the Atomic Mass weight of
196.97.
Round to the nearest whole number. The mass number of gold is
therefore 197.
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Example 2 - mass
number of Silver: The element Silver (Symbol Ag) has the Atomic
Number of 47. The number of protons in atom of silver is
therefore 47. Silver has the Atomic Mass weight of
107.87.
Round to the nearest whole number. The mass number of silver is
therefore 108.
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Example 3 - mass
number of Neon: The element Neon (Symbol Ne) has the Atomic
Number of 10. The number of protons in atom of neon is therefore
10. Neon has the Atomic Mass weight of 20.18. Round to the nearest
whole number. The mass number of neon is therefore
20.
Mass Numbers =
Atomic Weight of Element, rounded to nearest whole number
Mass numbers - Chart of Mass Numbers
The details all of the elements
in the Periodic table, the numbers of protons, the numbers of
neutrons and the mass numbers of atoms which relate to the
elements in the Periodic Table.
Chart of
Mass Numbers
Chart of
Mass Numbers
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