Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Fundamental Particles

Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now
X
Illustration You have already viewed an explanation Register now and access this and thousands of further explanations for free
Chemistry

Atoms are everywhere. In fact, (almost) everything in the known universe is made up of either atoms or empty space. And they are tiny - a 2.5g US copper penny contains roughlyatoms. But what exactly is an atom?

An atom is the smallest unit of an element.

The Ancient Greek philosopher Democritus was one of the first to believe in the existence of atoms over 2000 years ago. He believed that atoms were indestructible, had no internal structure, and that atoms of the same substance were all identical. Even the word atom itself comes from the Greek atomus, meaning indivisible. However, we know now he was only partially correct. Atoms contain smaller particles, called protons, neutrons and electrons. These particles are known as subatomic or fundamental particles, and the theory of subatomic particles and how they interact is known as the Standard Model.

Fundamental particles are particles found within an atom that aren't made of any other particle. This means that they can't be split up any further.

As mentioned above, there are three fundamental types of subatomic particles:

  • Protons.
  • Neutrons.
  • Electrons.

For this level of knowledge, we consider protons, neutrons and electrons as fundamental particles, meaning they aren't made of any other particle. But this isn't actually the case. Quantum scientists consider protons and neutrons to be made up of particles called quarks - a true fundamental particle. Electrons are a little different. When found orbiting in an atom or molecule, they can be split into three different particles called holons, spinons and orbitons, but if found outside of an atom or molecule, they can't be split up. This means that an isolated electron IS a fundamental particle, but an electron that is a part of an atom or molecule ISN'T.

Protons

Protons are positively charged particles. They are pretty small! In actual fact, one proton is only aboukg, but we tend to measure their mass using the carbon-12 scale. On this scale, everything is compared to 1/12 of the mass of a carbon-12 atom. Here protons have a mass of approximately 1.

You’ll find protons packed together densely in the nucleus in the centre of the atom. They’re quite important, because once you know the number of protons in an atom, you know where in the periodic table you’ll find it and what element it is a part of.

Neutrons

Neutrons are neutral particles with a relative mass of about 1. They are also found alongside protons in the nucleus. Neutron numbers can vary between atoms of the same element without changing their chemical properties.

Electrons

Electrons are negative particles. They are even smaller than protons - electrons have an actual mass of

, or a relative mass of 1/1840 on the carbon-12 scale. They aren’t found alongside protons and neutrons. Instead, electrons spend their time in energy levels, also known as shells, orbiting the nucleus. Energy levels increase in energy as they get further from the nucleus, and electrons always try to be in the lowest energy level possible. We’ll look at these further later on in the article.

The number of electrons in an atom determines its chemical properties and how it reacts.

Atoms have no overall charge, and this means they contain the same number of electrons as protons. If an atom gains or loses an electron to become a charged particle, it forms an ion.

An ion is an atom that has gained or lost an electron to form a charged particle.

The following table shows the relative masses and charges of the three fundamental particles:

Fundamental particles, proton neutron electron comparison, StudySmarterA table comparing protons, neutrons and electrons.StudySmarter Originals

Location of the fundamental particles

Back at the start of the twentieth century, the physicist JJ Thompson proposed that an atom contained small, negatively charged particles randomly scattered in a sea of positive charge. However, we now know that isn’t quite the case. An atom instead contains rings of electrons, known as shells, orbiting a dense mass called the nucleus.

The nucleus

Protons and neutrons are found densely packed together in the nucleus, the centre of the atom. You’ll remember that protons are positively charged whilst neutrons are neutral. This makes the nucleus positively charged too. However, particles with the same charge don’t really like hanging around together much - they tend to repel each other. An extremely powerful force called the strong nuclear force holds the protons and neutrons together in an impossibly small, dense mass.

Fundamental particles, strong nuclear force atom nucleus, StudySmarterThe strong nuclear force is responsible for holding the protons and neutrons in the nucleus together.
StudySmarter Originals

Electron shells

Unlike protons and neutrons, electrons are found in shells orbiting the nucleus. These shells are also known as energy levels, and are further arranged into subshells and orbitals. We’ll look at shells in more detail in the article "Electron shells, subshells and orbitals". However, you should know a few basics:

  • Electron shells are split into subshells that can each hold different numbers of orbitals and electrons.
  • Shells increase in energy as they get further from the nucleus.
  • Electrons are quite fussy and like being in the lowest energy state possible. When it comes to shells, they’ll always fill from the inside out if given the choice - so from the lowest energy level to the highest energy level.
  • Similarly, atoms really like having full outer shells of electrons. This means that they’ll often readily gain or lose electrons in order to complete their outer shell.
  • Shells don’t actually tell us where an electron is - in fact, it is impossible to know both the precise location of an electron and where it is headed. Instead, shells give us a rough approximation of where the electron will be the majority of the time.

Fundamental particles, carbon atomic structure, StudySmarterA representation of carbon’s atomic structure, showing electron shells surrounding the positively charged nucleus.

Unlike protons and neutrons, electrons are negative particles. They are attracted to the positive nucleus by a force called electrostatic attraction. However, this is much weaker than the strong nuclear force holding protons and neutrons together.

You should remember that although it may sound chaotic in an atom, with all the electrons rushing around the extremely dense, highly charged nucleus, the vast majority of the atom is actually empty space. Take a hydrogen atom, for example. It contains a single proton in its nucleus and is orbited by one electron. If the entire hydrogen atom was the size of the Earth, the proton itself would only be 200m across! Or to put it another way, if you blew up an atom to the size of a football stadium, its nucleus would only just be visible - it would be the size of a marble.

How do an atom’s fundamental particles influence its properties?

What makes hydrogen react so differently to helium? What causes sodium to fizz violently if placed in water whilst wetting carbon doesn’t appear to do anything? The three fundamental particles explored above determine an atom’s characteristics, the reactions it will undergo and which element it is a part of:

  • The number of protons determines which element the atom is in and its position in the periodic table. For example, each carbon atom has exactly six protons. If it were to lose a proton, it would become boron.
  • The combined number of protons and neutrons has little influence on the atom’s chemical properties, but increases its mass and so changes its physical properties.
  • The number of electrons present changes an atom’s chemical properties dramatically by changing its electron configuration. Remember that atoms prefer to have full outer shells of electrons, and their reactivity depends on how close their outer shells are to being full. Argon is a noble gas with a full outer shell, and so is relatively unreactive, whilst metals such as sodium, lithium and potassium must be stored in oil to stop them reacting with the air!

Fundamental Particles - Key takeaways

  • Atoms are made up of three fundamental particles called protons, neutrons and electrons.
  • Protons and neutrons are found in the nucleus at the centre of the atom whereas electrons are found in shells orbiting the nucleus.
  • Atoms are neutral and contain the same number of protons as electrons. An atom that has gained or lost an electron is called an ion.
  • The electron configuration of an atom determines its chemical properties whilst its proton number determines its position in the periodic table.

Fundamental Particles

Fundamental particles are particles found within an atom that aren't made up of any other particle.

The three fundamental particles are protons, neutrons and electrons.

By definition, fundamental particles aren't made up of any smaller particles.

Yes, electrons are fundamental particles.

Final Fundamental Particles Quiz

Question

What is an atom?


Show answer

Answer

The smallest unit of an element.

Show question

Question

What are the three fundamental particles?


Show answer

Answer

Proton, neutron and electron.


Show question

Question

What is the relative mass of a proton on the carbon-12 scale?


Show answer

Answer

1

Show question

Question

Which sentence is correct?


Show answer

Answer

Neutrons are neutral and have a relative mass of 1.

Show question

Question

Which sentence is correct?

Show answer

Answer

Protons and electrons have opposite charges.


Show question

Question

What is the relative mass of an electron?


Show answer

Answer

1/1840

Show question

Question

Where are protons found in an atom?


Show answer

Answer

In the nucleus.

Show question

Question

Where are electrons found in an atom?


Show answer

Answer

In shells orbiting the nucleus

Show question

Question

 Where are neutrons found in an atom?


Show answer

Answer

In the nucleus.

Show question

Question

Compare electrostatic forces with strong nuclear forces.


Show answer

Answer

  • Both electrostatic forces and strong nuclear forces are found in an atom. 
  • Electrostatic forces occur between electrons and the nucleus
  • The strong nuclear force acts between protons and neutrons, within the nucleus. 
  • The strong nuclear force is a lot stronger than electrostatic forces.


Show question

Question

Protons and neutrons are collectively referred to as nucleons. Give a reason for this.


Show answer

Answer

They are both found in the nucleus.

Show question

Question

2s is a lower energy shell than 2p. Predict which will get filled with electrons first.


Show answer

Answer

2s will get filled first.

Show question

Question

The electron shell 2s is further away from the nucleus than 1s. Predict which has a higher energy level.

Show answer

Answer

2s

Show question

Question

Which element contains eight protons?


Show answer

Answer

Oxygen

Show question

Question

When two hydrogen nuclei fuse, a proton is turned into a neutron. What element is the overall product?


Show answer

Answer

The overall product has one proton so is an isotope of hydrogen.


Show question

Question

 Predict what chemical, physical or other changes will occur when a lithium atom gains a proton


Show answer

Answer

It becomes beryllium, a new element.


Show question

Question

Predict what chemical, physical or other changes will occur when a lithium atom gains an electron.


Show answer

Answer

It changes chemical properties as it has a different electron configuration.


Show question

Question

 Predict what chemical, physical or other changes will occur when a lithium atom gains a neutron.


Show answer

Answer

It has slightly different physical properties as it has increased in mass.


Show question

Question

What is an electric field?

Show answer

Answer

Electric field is region around a charged particle in which other charged particles will experience a force.


Show question

Question

What is the force experienced by a charge "q" in electric field "E"

Show answer

Answer

F = q• E

Show question

Question

If there is a single positive point charge. where do the electric field lines originate?

Show answer

Answer

The charge

Show question

Question

Point A has stronger electric field than Point B. Which of the following statements is true?

Show answer

Answer

Electric field lines at A are denser than at B

Show question

Question

There is a positively charged flat surface with surface vector pointing up. What is the direction of electric field lines?

Show answer

Answer

Up

Show question

Question

q1 = 1C. q2 = -1C. distance between them (r) = 1m. What is the force on q2 due to q1, and in which direction?

Show answer

Answer

F = 9*10^9 Newtons towards q1.

Show question

Question

How can you create an electric field between surface A and surface B?

Show answer

Answer

By creating an electric potential difference between the two surfaces.

Show question

Question

q = 2C. Calculate the electric potential at point A which is 1m away from q.

Show answer

Answer

18*10^9 Volts 

Show question

Question

What is the direction of electric field at point A due to a -2C point charge kept 100m from it?

Show answer

Answer

Towards the Charge

Show question

Question

Select the true statement(s)

Show answer

Answer

Electric field lines tell us about the type of charge

Show question

More about Physical Chemistry
60%

of the users don't pass the Fundamental Particles quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

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

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.