2.1.1. Discovery of Electron

In 1830, Michael Faraday showed that if electricity is passed through a solution of an electrolyte, chemical reactions occurred at the electrodes, which resulted in the liberation and deposition of matter at the electrodes. He formulated certain laws that suggested the particulate nature of electricity.

Faraday's work highlighted that when an electric current passes through an electrolyte, it causes chemical changes. This was critical because it implied that electricity behaves like a particle rather than just a flow of energy. It suggested that there are discrete packets of charge, hinting that further research into the nature of these charges would be fruitful.

Imagine you have a big swimming pool (representing the electrolyte), and every time someone jumps in (the electric current), they displace water, causing splashes depending on how they jump. Similarly, electric currents cause reactions that can be seen, indicating the presence of something more tangible than merely energy.

In the mid 1850s, many scientists, mainly Faraday, began to study electrical discharge in partially evacuated tubes, known as cathode ray discharge tubes. When sufficiently high voltage is applied across the electrodes, current starts flowing through a stream of particles moving in the tube from the negative electrode (cathode) to the positive electrode (anode). These were called cathode rays.

Cathode ray tubes allowed scientists to visualize the behavior of electric currents in gases. When a voltage was applied, particles (later identified as electrons) emitted from the cathode traveled in straight lines towards the anode. Scientists could observe the effects of these particles hitting different materials within the tube, which led to further understanding of their properties.

Think about a garden hose with water flowing through it; if you put your finger partially over the end, the water streams out in a certain direction. In a cathode ray tube, the applying voltage is like turning on the tap, and the electrons are akin to the water being pushed through the tube.

The results of these experiments are summarized below: (i) The cathode rays start from cathode and move towards the anode. (ii) These rays themselves are not visible but their behavior can be observed with the help of certain kind of materials (fluorescent or phosphorescent). (iii) In absence of electrical or magnetic field, these rays travel in straight lines. (iv) In presence of electrical or magnetic field, the behavior of cathode rays is similar to that expected from negatively charged particles, suggesting that the rays consist of negatively charged particles, called electrons.

These observations were key in identifying the nature of cathode rays. They not only revealed that cathode rays traveled in straight lines unless influenced by external forces but also confirmed the inherent negative charge of these particles—now known as electrons. This set the stage for understanding atomic structure and subatomic particles.

It can be compared to how a magnet interacts with metal objects. If you were to throw some tiny metal filings into the air near a magnet, you’d see them align and move towards the magnet due to their opposite charges. Just like that, cathode rays are influenced by electric and magnetic fields, altering their paths and confirming their negative charge.

Thus, we can conclude that electrons are a basic constituent of all the atoms.

The conclusion that electrons exist within all atoms was revolutionary. It shifted the view of the atom from being a simple sphere of matter to a complex structure with both positive and negative components, establishing a foundation for modern atomic theory.

Imagine a chocolate chip cookie—where the dough represents the positive charge and the chocolate chips represent the electrons sprinkled throughout. This alteration from a basic structure to one with specific components reflects how our understanding of atoms evolved with the discovery of the electron.

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