Bohr"s atom,why the smalest orbit has the highest electrostatic force and its called the lowest energy level?

Answer 1

Electrostatic force diminishes with the square of the distance between objects exerting such force. So objects exerting electrostatic force that are close together will experience a much stronger force than objects further apart.

Why is it the lowest energy level? This is analogous to gravity. An object sitting on the edge of a bookshelf has higher potential energy than an equal object sitting on the floor. If the object on the bookshelf tips over and falls, it falls all the way to the floor where the potential energy is lower, whereas the object on the floor tips over, it just sits there and not much has changed. The object on the floor is closer to the object exerting force (the earth) and therefore is at a lower energy level. If it can't fall any further, (once you hit the floor, you're probably done falling unless there's stairs or something) it's at the lowest energy level.

Answer 2

Not just in the Bohr atom, but in the atoms described by true quantum mechanics (Bohr was a precurser and not completely right), the lowest energy level corresponds to the orbital closest to the nucleus (which has the higher force between the electrons and nucleus).

Why? It has to do with how we mathematically describe the energy. The higher force makes the electron more tightly bound, so it takes more energy to remove that electron from the atom. We set the lowest potential energy that an electron in the vicinity of a nucleus can have and NOT be bounded in the atom as zero. Positive (or zero) energy means that the electron is not bounded to the nucleus. Negative energy means that the electron is bounded to the nucleus. If the electron is bounded, it's energy corresponds to how much energy it takes to remove it from the atom. The tightest bound electron, of course, would require the most energy to remove it. This would make its value more negative than any other energy, thus it would be "lowest energy level" on an energy diagram.

This makes sense conceptually because a physical system tries to get into its lowest energy state. The lowest energy state of the whole system is one that is the most stable, and for the electron-nucleus system, it's the state with the highest force of attraction (lowest potential energy).

Answer 3

You probably mean Quantum Mechanics. The Neil’s Bohr model, which was based on convention or Newtonian physics, was discredited before the electrostatic forces involved inside the atom were looked at with any regularity. In fact one of the main features of Quantum Mechanics is the positioning of the electrons in their orbital shells. The Bohr Model has the electrons revolving in set circular orbits around the nucleus, when actually they are orbiting in probability patterns in dumbbell or circular orbits. It is impossible to determine exactly where an electron is in its orbit, since the act of detection will exert enough power on the atom to change its orbit; as per the Uncertainty Principle.

Chemical reactions are decided by how many electrons an atom is willing to share, or needs to fill up its highest orbital shell, with the magic number being 8 electrons. The innermost shell can only hold 2 electrons. Every succeeding higher shell holds a different amount of electrons and they are held by a looser strength from the nucleus, because they are farther away from the nucleus.

All electrons have the same electrostatic force, but their position in the nucleus determines how much energy is required to pull them out of the atom. Scientists were concerned with the actions of the outer shell of electrons, since that determines their chemical reactions. The inner electrons are only affected if the atom itself is destroyed. This is probably why you are referring to the innermost shell as being at the lowest energy level.

Answer 4

In Bohr's model, for each orbit, the electrostatic force of attraction is exactly balanced by the repulsive centrifugal force of the electron. This force arises because the electron is moving in a circle around the nucleus. So while an electron in the smallest orbit experiences the largest electrostatic force, it also experiences the largest centrifugal force, which means it is traveling very fast.

Answer 5

Because the electron lowers its potential energy as it moves closer to the nucleus (see gravity analogy answer). Then it takes more energy to get it out (higher electrosatic force) because you have to give it the energy to get back to where it was and then some.

Answer 6

He wasn't necassarily wrong. It was just that his model only represented small atoms, like that of Hydrogen.

Answer 7

Because he was wrong.