Atomic theory ect. Part 2 Flashcards
Absorption
When energy is absorbed by an atom, electrons jump up to higher and larger orbits
Niels Bohr
- Rutherford’s student
- made modifications to his atom model
- his model explained line spectra (connected Balmer’s math. relationship with Rutherford’s planetary model)
- proposed electrons orbit around the nucleus in circular paths of specific sizes
- each orbit has an energy level associated with it
2,8,8,18 - by combining Balmer’s equation with Planck’s equation - he calculated the energy dif. between orbits and the wavelength/frequency of light given off during fluorescence
- his diagram explains emission line spectrum of HYDROGEN
Emission/ fluorescence
These electrons can drop back down to lower orbits and in doing so they release energy in the form of light
Further experiments by Thomson and others using CRT’s discovered..
Proton
Sir James Chadwick discovered
neutron
Natural abundance
The amount of an isotope in a pure sample of the element expressed as a %
How do we get the natural abundances?
Mass spectrometer
Orbits
Two dimensional path around the nucleus in a Bohr’s diagram
Orbitals
Volumes of space
Can hold max 2 electrons
Almost all are overlapping and can share the Same space
S orbitals
Round and spherical
P orbitals
Two lobes down the Same axis
ALWAYS IN SET OF 3
D orbitals
ALWAYS COME IN SET OF 5
F orbitals
ALWAYS COME IN SETS OF 7
Exceptions
Cr. …4s1 3d5
Cu. …4s1 3d10
Electronic configuration
Description of the orbitals that are occupied by electrons in an atom or ion
Aufbau principle
Orbitals are filled one at a time starting with the lowest energy levels first. The lowest available energy orbital must be full before advancing to the next one
Pauli exclusion principle
No two electrons can be exactly the same in each orbital. Therefore if one orbital has 2 electrons, one must be spin up and the other must be spin down
Hund’s rule
When dealing with degenerate (the same energy level) orbitals, full each orbital with one electron first before pairing up
Isoelectric
Two chemical species that have the same electronic configuration
Means: The same energy level
Degenerate
What is used to observe a line spectrum?
Spectrometer
Emission line spectrum
The collection of the different colours of light that an element/substance emits
Isotopes
Atoms of the Same element with different masses due to a different number of neutrons
Ground state
State in which the electrons are in the lowest energy orbitals
Exited state
State in which the electrons are not in the lowest energy orbital
