Chapter 11 What subatomic particles do you get to play with? Protons Neutrons Eletrons changes the element isotopes: only mass is different what we play with in chemistry
Bohr Model of the Atom electrons must circle the nucleus of an atom in certain paths Developed the concept of Energy Levels Connected H s electron with photon emission 1.e - reside in orbits 2.Lowest energy closest to nucleus, increase in energy farther from nucleus 3.Empty space between each orbit 4.Calculated energies of an e - in allowed energy levels; E photon = h 5.e - in higher-energy orbits, falls back to lower-energy orbit releasing a photon 6.Calculated energies agreed with line series 7.Only explained H atom
Quantum (definition from Webster s) 1) quantity, amount 2) any of the very small increments or parcels into which many forms of energy are subdivided Quantum Theory -describes mathematically the wave properties of electrons and other very small particles *electrons were determined to have a dual wave-particle nature *uses two principles
Heisenberg Uncertainty Principle -it is impossible to determine simultaneously both the position and velocity of an electron or any other particle Schrodinger Wave Equation -treats electrons as waves around the nucleus *Together these determine the probability of finding electrons.
I. Louis de Broglie Could electrons have a dual wave-particle nature as well? A.e - be considered waves confined to the space around an atomic nucleus B.e - could only exist at specific frequencies, correspond to orbit energies C. Experiments confirmed hypothesis
Orbital -three-dimensional region around the nucleus that indicates the probable location of an electron To describe orbitals, we use.. Quantum Numbers -specify the properties of atomic orbitals and the properties of electrons in orbitals *there are 4 quantum numbers
Principle Quantum Number (n) -the main energy level occupied by the electron *positive integers *ranges from 1 to 7 *equals to the period Angular Momentum Quantum Number (l) -shape of the orbital *orbitals possible is equal to n *values of l are all integers less than l = n-1
Angular Momentum Quantum Number (l) l letter 0 s 1 p 2 d 3 f
Angular Momentum Quantum Number (l)
Magnetic Quantum Number (m) -indicates the orientation of an orbital around the nucleus * m = ±l Spin Quantum Number -has only 2 possible values (+½, -½)
Electron Configurations -the arrangement of electrons in an atom *based on 3 rules Afbau Principle -electrons occupy the lowest energy level they can
Pauli Exclusion Principle -no two electrons in the same atom can have the same set of four quantum numbers Hund s Rule -orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron and all electrons in singly occupied orbitals must have the same spin
Relative Energies of Orbitals
Electron Configuration Notation - the order of orbitals is. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6
Electron Configuration Notation Boron 5 electrons Bromine 35 electrons 1s 2 2s 2 2p 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5
Electron Configuration Notation Can also use Noble Gases to show Electron Configurations since they have fulfilled the Octet Rule Noble Gas Notation Bromine 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 [Ar] 4s 2 3d 10 4p 5
Filling Electrons using Afbau s Principle, the Pauli Exclusion Principle, and Hund s Rule Fill e- for: N O Al Br
Using Quantum Numbers to Identify Elements n l m spin N O Al Br 2 1 0 +1/2 2 0 0 +1/2