Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Quantum Numbers Mr Bohr wants to know Quantum Mechanical Model Is based on a mathematical probability of where electrons are located considers both particle and wave nature of electrons wave equation written for each electron Places electrons in orbitals, not orbits Quantum Numbers A set of 4 quantum numbers (and letters) that describe the probability of an electron being in a given location in an atom based on its energy level Each electron in the atom has a set of 4 unique numbers Orbitals region of space within which one can expect to find an electron no solid boundaries - “cloud” Each orbital has an electron capacity of 2 The Hierarchy of Quantum Numbers space surrounding nucleus divided up into large volumes called energy levels (1,2,3,4,5,6,7) Energy levels (shells) subdivided into smaller volumes called subshells (s,p,d,f) Subshells contain orbitals Electrons within orbitals have spin as shells get further from nucleus, energy, size, and electron capacity increase shells, subshells, orbitals, and spin are described by quantum numbers Principal Quantum Number - n Describes the energy level. Tells how far away from the nucleus the electron is Energy levels 1 to 7. The maximum number of electrons in n is 2n2. Orbital Quantum Number - l Describes the shape of the region (sublevel) the electron is probably in. Tells what sublevel the electron is in (s,p,d,f) Each energy level has n sublevels. Orbital Quantum Number: - l Sublevels of different energy levels may have overlapping energies. This is shown on the Periodic Table. Magnetic or Azimuthal Quantum Number - ml Tells what axis (x,y,z) the electron is probably on (the direction in space) Describes the orbital within a sublevel. s has 1 orbital p has 3 orbitals d has 5 orbitals f has 7 orbitals Orbitals may contain 1 or 2 electrons Spin Quantum Number - s Describes the spin of the electron. Electrons in the same orbital must have opposite spins. Possible spins are clockwise, +1/2, and counterclockwise, -1/2. s Orbital p Orbitals y y z x y px x z py x pz z d Orbitals y y z z y z x x dx2– 2 y dxy x y z x dz2 y z x dxz dyz Pauli Exclusion Principle No two objects can be in the same place at the same time OR: No two electrons in an atom have the same set of four quantum numbers. Electron Configuration 1s2 2s2 2p6 3s2 3p5 The large # is the electron energy level. The small letter is the sublevel. The superscript is the number of electrons in the sublevel. Read this from the Periodic Table. Electron Configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d3 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d9 Write the e-conf. for Bromine. Write the e-conf. for Lanthanum. Hund‘s Rule Electrons will enter empty orbitals of equal energy when they are available. Electrons Indicated by Shell and Subshell Symbolism #electrons nl# number letter Electrons Indicated by Shell and Subshell Symbolism #electrons nl# number 3s2 letter 5p5 4f14 Mr. Schroedinger has lost his cat ! End Quantum Numbers 24 22 20 18 16 14 12 H 10 8 V 6 o 4 l 2 t 1 2 s E l e c t r o n He 1 st Ionization Energy Ne F Ar N C Be P O Mg Cl S B Si Al Li Na 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Atomic Number