We will zoom inside sodium chloride crystal and explore its "atoms". You will see that sodium atoms are missing one electron, while chlorine atoms have one additional electron. In this way, you will be introduced to the concept of ions.
This lesson is a part of MEL Chemistry VR. Learn more →
atoms, ions, charged particles, electrons, anions, cations
- Learn that there are substances that consist not of atoms but of ions
- Find out how ions are formed
- See that the size of an atom and its ion are different
- Ions can be positive and negative
The aim is to show students that table salt being dissolved in water produces charged particles able to connect an electrical circuit.
Conduct the experiment described. Check that pure water doesn't conduct electricity. Put a pinch of table salt and see that the solution starts to conduct electricity. (Make a 10:1 consequential dilution to see when the solution stops conducting electricity).
History and sources of knowledge
- Faraday discovery of unknown “species” that travelled from one electrode to the other in aqueous media. Though he thought that these species were born under electrical current.
- Dissociation theory by Svante Arrhenius (Nobel Prize 1903). Ions are formed from crystalline substances when they are dissolved in water.
Topics to discuss
- Why the sodium atom is much bigger than the sodium ion?
- Why a chloride atom is smaller than a chloride ion?
- Substances are electrically neutral. There are no charged substances but there are charged particles forming electrically neutral substances.
Fun facts and quotes
- Calcium, sodium, and potassium ions are vital for the proper functioning of your body. Besides other important functions, they greatly affect how your heart works and your thinking process.
- Neon lights glow because of the formation of neon ions inside the lamp. Other noble gases can be used for different colours (helium: white to orange, neon: orange-red, argon: violet to lavender blue, krypton: off-white to green, xenon: dim blue-grey or intense green-blue).
- Ion engine to move a spaceship in space (xenon ions).
- The smallest ion is the hydrogen ion, which actually is just a proton. It's about 2,000 times smaller than a hydrogen atom.
- How can you form an anion (a negatively charged ion) from an atom?
- How can you form a cation (a positively charged ion) from an atom?
- What is greater for a negatively charged ion, the number of electrons or the number of protons?
- What is greater for a positively charged ion, the number of electrons or the number of protons?
- How many protons, electrons, and neutrons does Li+ have?
- How many protons, electrons, and neutrons does F- have?