atom + wavelength concepts and quantum mechanics 2

What did Democritus suggest?

Matter was made of tiny, invisible bits called “atomos.”

What did J.J. Thomson discover in 1897?

The electron

What model did Thomson propose?

A model with negative electrons floating in a positive “mist.”

What did Rutherford propose in 1911?

That atoms have an atomic nucleus.

When was the proton discovered?

1919

When was the neutron discovered?

1932

What is the nucleus made of?

Protons and neutrons

Where are the negative electrons relative to the nucleus?

They are outside/surrounding the positive nucleus.

What can individual atoms emit?

Light, producing an emission spectrum.

What does an emission spectrum tell us?

It shows the specific energy differences between electron energy levels in an atom and can identify the element.

What happens when an electron loses energy?

It drops to a lower energy level and emits light.

What happens when an electron gains the right amount of energy?

It jumps to a higher energy level.

Can an electron exist between two allowed energy levels?

No. It cannot be in between the energy levels.

What happens when an electron jumps between energy levels?

It absorbs or emits specific colors/wavelengths of light.

Where are the negative electrons relative to the nucleus?

They are outside/surrounding the positive nucleus.

What can individual atoms emit?

Light, producing an emission spectrum.