Models of Atomic structure

As solid spheres, with different spheres making up different elements

J.J. Thomson discovered the electron, showing atoms were not solid and indivisible, leading to the "plum pudding model."

A model where atoms were seen as a positive ‘pudding’ with negatively charged electrons scattered within it.

They conducted the gold foil experiment, firing positively charged alpha particles at a thin sheet of gold.

Most alpha particles passed straight through the gold, with only a few deflecting backward, indicating that the atom is mostly empty space.

The nuclear model, where a tiny positively charged nucleus is surrounded by a 'cloud' of negative electrons.

Electrons in a 'cloud' would spiral into the nucleus, causing instability.

He proposed that electrons exist in fixed shells or orbits of energy levels.

Electromagnetic radiation of fixed energy or frequency is emitted or absorbed.

Scientists found that electrons within the same shell could have different energies, leading to the concept of sub-shells.

It is simple and explains many experimental observations, like bonding and ionization energy trends.