Year 9, basics, paper 1&2 Flashcards
The atom
- nucleus with protons and neutrons,
- electrons on shells.
- most is empty space.
- neutral charge
Proton relative charge.
+1
Proton relative mass
1
Electron relative charge.
-1
Electron relative mass
1/1836 or nothing
Neutron relative charge
0
Neutron relative mass
1
John dalton
Thought atoms where:
- tiny hard spheres
- cant be broken down
- everything is made of these,
- cant be created or destroyed.
JJ Thomson
Discovered sub-atomic particles.
Atomic number =
Number of protons
Number of protons =
Number of electrons (in an atom)
Mass number =
Number of protons + neutrons
Mass number - atomic number =
Number of neutrons
Isotopes.
They are atoms which do not have the right amount of neutrons in there nucleus. So the atomic number and element remains the same however the mass number changes.
How to find RAM
RAM = (mass number x % of them) + (mass number x % of them)
————————————————————————
100
Rutherford
Discovered atoms were mainly empty space.
In isotopes
- change of physical properties
- same chemical.
Mendeleeves table was not believed at first why?
- metals where put with non metals
- switched some elements around.
- groupie 8 was missing.
Periodic table nowadays
- ordered in atomic number
- still groups in chemical and physical properties.
- rows = period
- columns = groups
- metals on left, non metals right,
Group 7
- halogens
- right, non metals
- toxic
- low melting
- poor conductors
- all look different.
Group 1
- reactive the further down the group.
- on the left.
- called the alkali metals.
