The Beauty of knowing (1): How we “think” Atom is!
Atom? Like the solar system, right? Nope! Do not be sorry. If we time travel just 150 years back and ask the most intelligent man on Earth this very question he will probably say, “We are not sure if atoms exist in the first place!”
Story: A few guys take a vaccum glass tube with one end connected to the positive and the other to the negetive end of the supply and turn on the power. BAM! There is suddenly light flowing from negetive to positive! Since it originates at the negetive end they conclude the light must be negetive. They name this “ray” of light after the negetive end that produces it: Cathode ray (Yeah! The same phenomenon behind grandpa TV!) But another man finds that the positive end also emits an opposite ray. Thus, the “ray” cannot be negetive. Meanwhile, someone else finds that this “light” has weight! What! How can light, which has no mass, have weight? Finally they conclude that this “light” is not light! But what? To make things worse they find that these “what-ever-they-are” are far lighter than Hydrogen, the lightest element known to man! So, it has weight, but is lighter than the lightest atom! Conclusion: Atom is made up of smaller things. Now that they know what they are dealing with, things get easier. They name the negetive things electrons and the positive things protons. Now then, how are they arranged? For those of my friends who remember the names of J.J. Thomson, Goldstein, Rutherford, Bohr, somerfield and so on, and yet not know what they said, let this story still proceed without names.
First theory: Imagine a circular fruit cake; the cake is proton matrix and tiny fruits are electrons (because they only move around.)
But another man passes some positive rays (which will later be called alpha rays) through a thin foil. Most rays pass through, but a few deviate in all kind of angles. Positive rays can only be deviated other positive things, right? The whole same charges repel fact! Furthermore, the zones of deviations are so very few compared to the huge passing-through areas and this indicates only one thing: Protons are restricted to a teeny-tiny portion of an atom. Voila! This leads to “the nucleus is in the middle of the atom” axiom and eventually the discovery of the neutron. But back to the arrangement.
Theory 2: Planetary type, with the electrons orbiting the nucleus in orbits based on energy level.
But things do not add up. Another guy comes in and says it is not possible to pin-point the location of an electron at any given instant. In fact, it so happens that, simultaneously an electron can be in more than one place! Freaky, right? If your rational mind cannot accept it, do not worry, mine cannot either, but that is how things are! They try to explain it with partially abandoning what they have found and partially accepting what they had abandoned earlier: electrons are both particles and waves and neither particle nor waves! (Let both the reader and writer rest in peace!)
Theory 3: Balloon type: So, if you cannot say for sure where the electron can be, just assume! I am not joking. That is what is being done. Using a mathematical too (wave theory) they predict the location of electrons at any given time and select the zone with highest probability and shade it with the nucleus at the centre. It seems to be something like this: Based on the number of orbitals (orbitals are energy levels, and again not that simple; because energy levels seem to mate with one another forming all sorts of patterns) imagine balloons tied together at the opening (nucleus) in the appropriate pattern.
Theory 4: This is the most relevant theory (at least, for the time being): In the previous theory it was taken for granted to take the portions around the nucleus that had highest probability as the place where an electron could be. But what if an electron is found in a region of very low probability? Just because something is improbable does not mean it is impossible! Thus comes THE CLOUD MODEL: A nucleus at the centre. Around it, based on the probability of the presence of electron colour shading is given.
Now then, if someone dares to ask you if you know anything about quantum theory (about sub-atomics) throw all this at them!
