Electronic Structure Flashcards
Ultraviolet light
- A form of electromagnetic radiation characterised by its frequency (v, nu) and wavelength (lamda)
- little packets of energy called photons
John Dalton’s Contribution 1803
- matter is made up indivisible particles (atoms)
- atoms of an element have the same properties e.g mass
- chemical reactions: atoms changing the way they are combined to one another i.e atoms combing to form molecules + atoms of a molecule interacting with atoms of another molecule
- atoms in fixed ratios of whole numbers
Atomic mass
The mass of atom of an element relative to the mass of the carbon-12 atom
Newtons rainbow spectrum
The sun has lots of different atomic species giving out different coloured light. This gives the continuous spectrum we associate with sunlight.
Fraunhofer’s dark lines
Atomic species in the sun’s atmosphere absorb photons of light of a particular colour (wavelength/frequency). These missing photons are responsible for the dark lines in the sun’s continuous spectrum
Spectra produced by cathode ray tubes
The pattern of lines in a family getting closer together as we go towards the blue/violet (high energy) end of the spectrum, is due to the fact that the energy levels available to the electrons get closer together as we move away from the nucleus
Orbit
Fixed 2D path for an electron of definite mass. Does not comply with uncertainty principle is disregarded
Orbital
A volume of space (3D) in which there is a high probability of finding an electron
Energy level
A region of definite energy within an atom that electrons can occupy
Discoveries that lead to the concept of the orbital
- Einstein’s relativity
- de Broglie’s theory
- Heisenberg’s uncertainty principle
Rule 1: the Aufbau principle
Electrons fill the lowest energy level available
Rule 2: the Pauli Exclusion Principle
Each individual energy level can hold two electrons
Rule 3: Hund’s rule of Maximum Multiplicity
Each energy level of the same energy are filled singly before pairing occurs
