Neutron Number

TABLE OF CONTENTS :

TABLE OF CONTENTS

Save the explanation now and read when you’ve got time to spare.

Save

Lerne mit deinen Freunden und bleibe auf dem richtigen Kurs mit deinen persönlichen Lernstatistiken

Jetzt kostenlos anmelden

Nie wieder prokastinieren mit unseren Lernerinnerungen.

Jetzt kostenlos anmelden

The neutron number refers to the total number of neutrons in the nucleus. If the number of neutrons is larger than the number of protons, the atom has a neutron excess.

Reading the neutron number

To identify the neutron number, you need to read the element’s nuclide notation. The neutron number is located in the lower right corner of the nuclide notation, as in this example of Iron 56:

\[^{56}_{26}Fe_{30}\]

However, the neutron number is not always specified and thus may need to be calculated.

Neutron Numbers. Atom model of tritium. Vaia Figure 1. Tritium, which is an isotope of hydrogen. Its nuclide notation indicates that there are three particles in the nucleus: one proton and two neutrons. Source: Manuel R. Camacho, Vaia.

Calculating the neutron number

To calculate the neutron number, use the nuclide notation as shown below:

\[\text{Neutron number} = (\text{Mass number - Atomic number})\]

In the case of Iron 56, this looks as follows

\(\text{Neutron number} = (56 - 26) = 30\)

Neutron excess

The nuclide notation defines the number of particles in the nucleus in the upper-left corner, while the number of protons is given in the lower-left corner, as in this example of Iron 56:

\[^{56}_{26}Fe_{30}\]

Iron has 26 protons, as indicated by the atomic number in the lower-left corner, and a total of 56 particles in the nucleus, as shown in the upper-left corner. You might expect the number of protons and other particles in the nucleus to be equal, but that is not the case. Multiplying 26 by two would give you 52, whereas the atomic number 56 indicates that there are four additional particles in the atom’s nucleus. There is, therefore, a neutron excess of four.

Neutrons and isotopes

An atom with either a lack or an excess of neutrons is called an isotope. Some isotopes break up after some time, which produces radiation in the form of particles such as photons, beta particles and others. There can be many isotopes for a single atomic element.

Neutron Numbers. Isotopes. Hydrogen. Vaia Figure 2. Hydrogen isotopes with different numbers of neutrons in the nucleus. From left to right: no neutron, one neutron, and two neutrons. Source Manuel R. Camacho, Vaia.

What is a neutron?

A neutron is a particle located in the centre of an atom alongside protons. Both neutrons and protons are also known as nucleons. Neutrons have a neutral charge and are one of two types of particles that contribute a greater amount of mass to an atom. The characteristics of neutrons are shown below:

Particle	Mass in kilograms	Electrical charge in coulombs	Location
neutron	\(1.67 \cdot 10 ^{-27}\)	0	Nucleus

Neutrons and the atom’s mass

Neutrons are one of two types of particles that make up most of an atom’s mass. The more neutrons an atom has, the heavier it is. Neutrons have a mass that is 1836.15 times larger than that of an electron and are just a bit heavier than protons.

Neutrons and the atom’s charge

Neutrons have a neutral electrical charge. Because of this, when an atom has a neutron excess, it does not change its electrical nature.

Neutrons and the atom’s relative charge

When thinking about atomic charges, it helps to work with the concept of relative charge. The relative electrical charge of a neutron is 0. A neutron’s relative charge is indicated as below:

\[0^n\]

Neutron Numbers - Key takeaways

The neutron number indicates how many neutrons there are in total in an element's atom.
The difference between the neutron number and the atomic number indicates the neutron excess.
Neutrons are one of two particles that add a significant amount of mass to an atom.
Neutrons are almost 1836.15 times heavier than electrons.
Neutrons and protons have similar masses.
Neutrons have a neutral charge and only add mass to an atom.

Frequently Asked Questions about Neutron Number

To determine the number of neutrons, you need to read the nuclide notation and apply the following formula:

Neutron number = Mass number-Atomic number.

The neutron number indicates the number of neutrons in an atom.

Neutron excess indicates that there are more neutrons than protons in the atom’s nucleus. It is determined by subtracting the number of protons from the number of neutrons.

Final Neutron Number Quiz

Neutron Number Quiz - Teste dein Wissen

Question

What is the neutron number?

Show answer

Answer

The number of neutrons in an atom.

Show question

Question

Where is the neutron number in the nuclide notation?

Show answer

Answer

In the bottom right corner.

Show question

Question

What is the neutron number in this element: Fe 56?

Show answer

Answer

30.

Show question

Question

Which data do you need to calculate the neutron number?

Show answer

Answer

The atomic number and the mass number.

Show question

Question

What is neutron excess?

Show answer

Answer

Neutron excess exists when there are fewer protons than neutrons.

Show question

Question

What is a neutron?

Show answer

Answer

An atomic particle that is located in the atom’s nucleus.

Show question

Question

What is the mass of a neutron?

Show answer

Answer

1.67 x 10^-27 kg.

Show question

Question

What is the charge of a neutron?

Show answer

Answer

Show question

Question

What is the elemental charge of an electron?

Show answer

Answer

-1.

Show question

Question

What is the neutron symbol?

Show answer

Answer

Show question

Question

In percentage, how similar are the masses of neutrons and protons?

Show answer

Answer

99.8%.

Show question

Question

How large is the mass of a neutron compared to that of an electron?

Show answer

Answer

It is 22,000 times larger.

Show question

Question

If the atom has an excess of charge, does that change its electrical charge?

Show answer

Answer

No, it doesn’t.

Show question

Question

Neutrons are particles that contribute mass to the atom. True or False?

Show answer

Answer

True.

Show question

Question

Where are neutrons located?

Show answer

Answer

In an atom’s nucleus.

Show question

Question

What is another name for neutrons?

Show answer

Answer

Protons and neutrons are also jointly known as nucleons.

Show question

Question

What is the effect of there being more neutrons in an atom?

Show answer

Answer

It makes the atom heavier.

Show question

Question

What is the name of an atomic element with an excess of neutrons?

Show answer

Answer

Isotope.

Show question

Question

What can happen when an atom has more neutrons than protons?

Show answer

Answer

The atom can break into smaller particles such as electrons, alpha particles, and elements of lower atomic mass.

Show question

Question

What happens when, due to an excess of neutrons, the atom breaks into smaller particles?

Show answer

Answer

It produces radiation.

Show question

More about Neutron Number

How would you like to learn this content?

Creating flashcards

Studying with content from your peer

Taking a short quiz

How would you like to learn this content?

Creating flashcards

Studying with content from your peer

Taking a short quiz

Free physics cheat sheet!

Everything you need to know on . A perfect summary so you can easily remember everything.

Email Address*

Select your language

Neutron Number

Reading the neutron number

Calculating the neutron number

Neutron excess

Neutrons and isotopes

What is a neutron?

Neutrons and the atom’s mass

Neutrons and the atom’s charge

Neutrons and the atom’s relative charge

Neutron Numbers - Key takeaways

Frequently Asked Questions about Neutron Number

How do we determine the number of neutrons?

What is the neutron number?

What is neutron excess?

Final Neutron Number Quiz

Neutron Number Quiz - Teste dein Wissen

More explanations about Radiation

Discover the right content for your subjects

Biology

Business Studies

Chemistry

Combined Science

Computer Science

Economics

Engineering

English

English Literature

Environmental Science

Geography

History

Human Geography

Law

Macroeconomics

Marketing

Math

Microeconomics

Politics

Psychology

Sociology

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Quizzes

Flashcards

Notes

Study Sets

Documents

Study Analytics

Weekly Goals

Smart Reminders

Rewards

Magic Marker

Smart Formatting

Join millions of people in learning anywhere, anytime - every day

This is still free to read, it's not a paywall.

You need to register to keep reading

This is still free to read, it's not a paywall.

You need to register to keep reading

Start learning with StudySmarter, the only learning app you need.

Create a free account to save this explanation.

StudySmarter bietet alles, was du für deinen Lernerfolg brauchst - in einer App!