Atomic Structure Flashcards
Atoms into ions
When atoms either lose or gain electrons they form ions
Cation
These are positive ions and form when atoms lose electrons
Anions
These are negative ions and form when atoms gain electrons
What did Dalton state
All elements made up of small particles called atoms
What did JJ Thomson do
Plum pudding model, stated negative electrons embedded in a positive sphere
What did Rutherford do
Model had negative electrons orbiting a positive nucleus
What did Chadwick do
Discovered the neutron
Present day
Protons and neutrons in the nucleus and electrons orbiting around in shells
Atomic number
Number of protons in an atom
Mass number
The total number of protons and neutron in (the nucleus of) and atom
Relative mass (atomic mass units) in a proton
1
Relative mass (atomic mass units) in a neutron
1
Relative mass (atomic mass units) in an electron
1/1840
Relative charge of a proton
+1
Relative charge of a neutron
0
Relative charge of an electron
-1
Proton position in an atom
Nucleus
Neutron position in an atom
Nucleus
Electron position in an atom
Shell
Electrons in an orbit
- Electrons are arranged in shells around the nucleus.
- The electrons enter the shell closest to the nucleus first.
- Each shell must be filled with its full quota before starting to fill the next shell.
- Shell number 1 (closest to the nucleus) can take a maximum of 2 electrons
- All other shells have a maximum of 8 electrons
Isotopes
Isotopes are atoms which have the same number of protons (so they are atoms of the same element) but they have a different number of neutrons (so they have a different mass number).
Two common isotopes of chlorine
Chlorine- 35
Chlorine - 37
Chlorine - 35 number of protons, electrons and neutrons
17 protons
17 electrons
18 neutrons
Chlorine - 37 number of protons, electrons and neutrons
17 protons
17 electrons
20 neutrons
