Topic 1: Atomic structure Flashcards
First ionisation energy definition
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms of the element, forming 1 mole of gaseous atoms with a +1 charge
Order of sublevels
S, P, D, F
Aufbau principle
1) Subshells fill in orger of increasing energy
2) A subshell must fill before moving onto the next
3) Orbitals can hold 2 electrons MAX
4) In subshells with orbitals of equal energy- one electron goes into each orbital before spin pairing occurs
2 exceptions to aufbau principle
Copper and chromium
What affects the first ionisation energy
- Charge on nucleus
- Distance (Atomic radius)
- Sheilding
- Repulsion
- Energy of the subshell
Reason for general increase across a period (electronegativity)
- Nuclear charge increases
- Sheilding doesn’t change
- Atomic radius gets smaller
Reasons for general decrease down a group (Ionisation energy)
- Increased distance
2. Increased sheilding
Stages of mass spectometry
- Ionisation
- Acceleration
- Ion drift
- Detection
Acceleration in mass spec
Ions accelerated at a constant kinetic energy by and electric field
Detection
Positive ions hit detector and gain electrons
This movement is detected as current + the time of striking is recorded
Types of ionisation for mass spec
Option 1) Electron Impact ionisation -
Sample vaporized
Bombard with high energy electrons
Option 2- Large molecules) Electrospray ionisation- High voltage in a polar solvent
Ion drift
Enter a flight tube with no electric field
Ions are separated based on different velocities