Atom structure

In this lesson, you will learn that an atom consists of a tiny atomic nucleus surrounded by an electron cloud. We will discuss the three main subatomic particles: protons, neutrons and electrons, and their properties.

This lesson is a part of MEL VR Science Simulations. Learn more →

Teacher's notes

Key­words

atoms, elec­trons, nu­cle­us, pro­tons, neu­trons, coulomb forces

Com­mon mis­con­cep­tions

• Grav­i­ty is one of the forces pulling nu­clei and elec­trons to­geth­er.
• Plan­e­tary mod­el: elec­trons move around the nu­cle­us.

Stu­dents will

• Learn that the atom con­sists of a pos­i­tive­ly charged nu­cle­us and neg­a­tive­ly charged elec­trons
• Learn that a nu­cle­us con­sists of pro­tons and neu­trons
• Learn about the forces that bring nu­cle­us and elec­trons to­geth­er
• See that elec­trons spread around the nu­cle­us like a cloud
• Learn that the nu­cle­us is much heav­ier than elec­trons
• Learn the rel­a­tive dis­tance from the nu­cle­us to elec­trons com­pared to nu­cle­us size

Hands-on ac­tiv­i­ties

Af­ter VR

The aim is to give stu­dents an idea that the nu­cle­us is much heav­ier than elec­trons.

Ask stu­dents to weigh a 2-litre bot­tle of wa­ter. Then cal­cu­late the weight of an elec­tron, as­sum­ing that the bot­tle weight rep­re­sents the mass of a pro­ton. Ask stu­dents to weigh a piece of play­dough rep­re­sent­ing an elec­tron.

Top­ics to dis­cuss

• How and where atoms are formed.
• It’s not cor­rect to say that atoms are most­ly an emp­ty space.
• The weight of pro­tons and neu­trons as com­pared to elec­trons.

Fun facts and quotes

• The largest an­i­mal that now ex­ists on Earth is a blue whale. Its length is up to 30 me­tres and a weight of up to 180 tons. If we re­place all the atoms that form a blue whale with their nu­cle­us the length of the an­i­mal would be 0.3 mm (it's close to the small­est ob­ject we can see with naked eyes). And the weight would not change at all.
• In neu­tron stars, all mat­ter is denser (up to 10 times) than in an atom nu­cle­us.
• The force of grav­i­ty be­tween the nu­cle­us and elec­trons is 1 and 42 ze­ros weak­er than the elec­tro­stat­ic force ac­tu­al­ly hold­ing them to­geth­er.
• Most of the atoms in the uni­verse are from su­per­no­va ex­plo­sions.

Ques­tions

• Name sub­atom­ic par­ti­cles.
• Which sub­atom­ic par­ti­cles are charged?
• Which sub­atom­ic par­ti­cles are not charged?
• Which is heav­ier elec­tron or neu­tron?
• Which is heav­ier elec­tron or pro­ton?
• What is the force hold­ing nu­cle­us and elec­trons to­geth­er?

Cal­cu­lat­ing

The elec­tron is ap­prox­i­mate­ly 2,000 times lighter than a pro­ton. Cal­cu­late the mass of an elec­tron as a per­cent­age of the pro­ton mass.