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 Chemistry VR. Learn more →
atoms, electrons, nucleus, protons, neutrons, coulomb forces
- Gravity is one of the forces pulling nuclei and electrons together.
- Planetary model: electrons move around the nucleus.
- 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
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.
History and sources of knowledge
- Old theories that atoms are not divisible.
- Thomson’s discovery of electrons.
- Rutherford gold-foil experiment.
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.
- 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?
The electron is approximately 2,000 times lighter than a proton. Calculate the mass of an electron as a percentage of the proton mass.