Chem 8.1 Atomic Structure Flashcards
What does a scientific model describe?
An object, system, or idea.
Scientists used to use the solid atom model to explain what?
To explain behaviour of solids, liquids, and gases; diffusion; density; and gas pressure.
What could the solid atom model NOT explain?
How atoms join together; and chemical reactions.
In 1932, a new atom model was made. What was this model about?
It states that atoms are made up of tiny sub-atomic particles. This model could now explain chemical reactions and how atoms join together.
What are the 3 sub-atomic particles?
Protons, Neutrons, and Electrons.
What are the relative masses of the sub-atomic particles?
Proton – 1
Neutron – 1
Electron – 1/1840
What are the charges of the sub-atomic particles?
Proton – +1
Neutron – 0
Electron – -1
What makes up the nucleus of an atom?
Protons and Neutrons
Where do electrons whizz about?
In orbits or shells around the outside.
Why is almost all of the atom’s mass in the nucleus?
The nucleus is made up of protons and neutrons that are heavier than electrons. However, the size of the nucleus is very tiny, making the nucleus have a high density.
Why do atoms have no overall electric charge?
Atoms are neutral because, in every atom, the number of protons is THE SAME as the number of electrons.
This means that the positive charge (proton) and the negative charge (electron) cancels out.
