Our current model Flashcards
What is the atom like
The atom is a positively charged nucleus surrounded by negatively charged electrons
Where is all the mass of the atom
It is in the nucleus
How big is the nucleus
It’s tiny, about 10,000 times smaller than the whole atom
What does the nucleus contain
Protons which are positively charged and neutrons which are neutral. The rest of the atom is mostly empty space
What do the negative electrons do
They whizz round the outside of the nucleus in fixed orbits called energy levels or shells
What is the overall size around a shell
-10
1 x 10 m
Why are atoms neutral
The number of protons=the number of electrons. This is because protons and electrons have an equal but opposite relative charge
What happens when an atom loses an electron
It becomes a positive ion
What happens if it gains an electron
It becomes a negative ion
What can atoms do
They can join together to form molecules e.g. molecules of oxygen gas are made up of two oxygen atoms bonded together
What does small molecules have the typical size of
-10
10 m
The same sort of scale as an atom
What is the relative mass of a proton
1
What is the relative mass of a neutron
1
What is the relative mass of an electron
1/2000 or 0.0005
What is the relative charge of a proton
+1
