How to Find the Number of Protons, Neutrons, and Electrons
Get a periodic table of elements., Find your element on the periodic table., Locate the element’s atomic number., Determine the number of electrons., Look for the atomic mass of the element., Subtract the atomic number from the atomic mass...
Step-by-Step Guide
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Step 1: Get a periodic table of elements.
The periodic table is a chart that organizes elements by atomic structure.
It is color coded and assigns each element a unique 1, 2, or 3-letter abbreviation.
Other elemental information includes atomic weight and atomic number.You can find a periodic table online or in a chemistry book.
In tests, normally, a periodic table will be provided. -
Step 2: Find your element on the periodic table.
The table orders elements by atomic number and separates them into three main groups: metals, non-metals, and metalloids (semi-metals).
Further elemental groupings include alkali metals, halogens, and noble gases.Using the group (columns) or period (rows) can make the element easier to locate on the table.
You can also search the table for the symbol of the element if you don’t know any other properties. , The atomic number is located above the element symbol, in the upper left-hand corner of the square.
The atomic number will tell you how many protons make up a single atom of an element.For example, boron (B) has an atomic number of 5, therefore it has 5 protons. , Protons are particles in the nucleus of an atom that have a positive charge.
Electrons are particles that have a negative charge.
Therefore, an element in a neutral state will have the same number of protons and electrons.
For example, boron (B) has an atomic number of 5, therefore it has 5 protons and 5 electrons.
However, if the element includes a negative or positive ion, then the protons and electrons will not be the same.
You will have to calculate them.
The ion number will appear as a small, superscript after the element. , To find the number of neutrons, you will first need to find the atomic mass.
An element’s atomic mass (also known as the atomic weight) is the average mass of atoms of an element.The atomic mass can be found underneath the symbol for the element.
Make sure that you round the atomic mass to the nearest whole number.
For example, the atomic mass of boron is
10.811, but you can just round the atomic mass up to
11. , To find the number of neutrons, you will need to subtract the atomic number from the atomic mass.
Remember that the atomic number is the same as the number of protons, which you have already identified.For our boron example, 11 (atomic mass) – 5 (atomic number) = 6 neutrons , The number of ions in an element will appear as a small, superscript number following the element.
An ion is an atom that has a positive or negative charge due to the addition or removal of electrons.Although the number of protons in the atom remains the same, the number of electrons is altered in an ion.
Because an electron has a negative charge, when you remove electrons, the ion becomes positive.
When you add more electrons, the ion becomes negative.
For example, N3- has a
-3 charge while Ca2+ has a +2 charge.
Keep in mind that you do not have to do this calculation if there is no superscripted ion number following the element. , When an ion has a positive charge, the atom has lost electrons.
To calculate the remaining number of electrons, you subtract the amount of extra charge from the atomic number.
In the case of a positive ion, there are more protons than electrons.
For example, Ca2+ has a +2 charge so it has lost 2 electrons from the neutral state.
Calcium’s atomic number is 20, therefore the ion has 18 electrons. , When an ion has a negative charge, the atom has gained electrons.
To calculate the total number of present electrons, you simply add the amount of extra charge to the atomic number.
In the case of a negative ion, there are fewer protons than electrons.
For example, N3- has a
-3 charge therefore it has gained 3 electrons compared to the neutral state.
Nitrogen’s atomic number is 7, therefore this ion has 10 electrons. -
Step 3: Locate the element’s atomic number.
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Step 4: Determine the number of electrons.
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Step 5: Look for the atomic mass of the element.
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Step 6: Subtract the atomic number from the atomic mass.
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Step 7: Identify the number of ions.
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Step 8: Subtract the charge from the atomic number.
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Step 9: Add the charge to the atomic number for negative ions.
Detailed Guide
The periodic table is a chart that organizes elements by atomic structure.
It is color coded and assigns each element a unique 1, 2, or 3-letter abbreviation.
Other elemental information includes atomic weight and atomic number.You can find a periodic table online or in a chemistry book.
In tests, normally, a periodic table will be provided.
The table orders elements by atomic number and separates them into three main groups: metals, non-metals, and metalloids (semi-metals).
Further elemental groupings include alkali metals, halogens, and noble gases.Using the group (columns) or period (rows) can make the element easier to locate on the table.
You can also search the table for the symbol of the element if you don’t know any other properties. , The atomic number is located above the element symbol, in the upper left-hand corner of the square.
The atomic number will tell you how many protons make up a single atom of an element.For example, boron (B) has an atomic number of 5, therefore it has 5 protons. , Protons are particles in the nucleus of an atom that have a positive charge.
Electrons are particles that have a negative charge.
Therefore, an element in a neutral state will have the same number of protons and electrons.
For example, boron (B) has an atomic number of 5, therefore it has 5 protons and 5 electrons.
However, if the element includes a negative or positive ion, then the protons and electrons will not be the same.
You will have to calculate them.
The ion number will appear as a small, superscript after the element. , To find the number of neutrons, you will first need to find the atomic mass.
An element’s atomic mass (also known as the atomic weight) is the average mass of atoms of an element.The atomic mass can be found underneath the symbol for the element.
Make sure that you round the atomic mass to the nearest whole number.
For example, the atomic mass of boron is
10.811, but you can just round the atomic mass up to
11. , To find the number of neutrons, you will need to subtract the atomic number from the atomic mass.
Remember that the atomic number is the same as the number of protons, which you have already identified.For our boron example, 11 (atomic mass) – 5 (atomic number) = 6 neutrons , The number of ions in an element will appear as a small, superscript number following the element.
An ion is an atom that has a positive or negative charge due to the addition or removal of electrons.Although the number of protons in the atom remains the same, the number of electrons is altered in an ion.
Because an electron has a negative charge, when you remove electrons, the ion becomes positive.
When you add more electrons, the ion becomes negative.
For example, N3- has a
-3 charge while Ca2+ has a +2 charge.
Keep in mind that you do not have to do this calculation if there is no superscripted ion number following the element. , When an ion has a positive charge, the atom has lost electrons.
To calculate the remaining number of electrons, you subtract the amount of extra charge from the atomic number.
In the case of a positive ion, there are more protons than electrons.
For example, Ca2+ has a +2 charge so it has lost 2 electrons from the neutral state.
Calcium’s atomic number is 20, therefore the ion has 18 electrons. , When an ion has a negative charge, the atom has gained electrons.
To calculate the total number of present electrons, you simply add the amount of extra charge to the atomic number.
In the case of a negative ion, there are fewer protons than electrons.
For example, N3- has a
-3 charge therefore it has gained 3 electrons compared to the neutral state.
Nitrogen’s atomic number is 7, therefore this ion has 10 electrons.
About the Author
Martha Murphy
Creates helpful guides on cooking to inspire and educate readers.
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