Zusammenfassung der Ressource
Atomic Structure
- Fundamental Particles
that compose atoms
- Protons
- Found in nucleus
- relative mass = 1
- Relative charge = +1
- Neutrons
- Found in nucleus
- Relative mass =1
- Relative charge = 0
- Electrons
- Surround the nucleus
- Relative mass = 1/1840
- Relative Charge = -1
- The arrangement of
the electrons
- Electron shells
- 1st shell = 2 electrons
- 2nd shell = 8 electrons
- 3rd shell = 18 electrons
- General
formula
- number of electrons in shell = 2n²
- Electron Diagrams
- write the number of electrons in each shell,
- inner shell first
- Separate numbers with a comma
- e.g carbon would be 2,4
- Mass number, atomic
number and isotopes
- Mass Number, A
- Number of protons +
number of neutrons
- the is because the
electrons weigh
virtually nothing
- Atomic Number, Z
- Equal to the number of protons
- All atoms of the same
element have the same
atomic number.
- Isotopes
- Atoms with the same number
atomic number, but a different
mass number
- i.e they have a
different number of
neutrons
- Mass Spectrometry
- Ionisation
- beam of electrons knock an electron
form the outer shell of the sample
- This makes them positive ions
- Acceleration
- Positive ions are attracted to
negatively charge plates
- Causing the ions to accelerate, the
lighter they are the faster they go
- Deflection
- beam is moved into a magnetic field at
right angle to the direction of travel
- Deflection depends on the ratio of its mass
to charge, heavier ions are deflected less
- Detection
- The magnetic field is gradually increased so that
the ions enter the detector one after another
- The ions strike the detector and
accept an electron so they are no
longer ions