Quantum Numbers PDF

Quantum Numbers  Every electron in an atom can be described by a unique combination of 4 quantum numbers (kind of like an address) 1) The Principal Quantum Number (n) n describes an orbital in terms of its distance from the nucleus (main energy levels surrounding the nucleus) These...

Quantum Numbers  Every electron in an atom can be described by a unique combination of 4 quantum numbers (kind of like an address) 1) The Principal Quantum Number (n) n describes an orbital in terms of its distance from the nucleus (main energy levels surrounding the nucleus) These levels are often referred to as shells (a shell is a collection of orbitals) Describes the main lines of bright-line spectra The value of n is an integer that ranges from 1-infinity The larger the value of n, the greater the distance of an electron in an orbital from the nucleus and the larger and less stable the orbital 2) The Secondary Quantum Number (l) Describes the approximate shape of an orbital Within each main energy level beyond the first, orbitals with different shapes occupy different regions in space These regions are referred to as sublevels or subshells Orbitals with the same n but different l belong to different subshells and are denoted by the letters s, p, d, f s p These smaller subdivisions also indicate the energy associated with electrons in a secondary manner (s< p< d< f) 3) The Magnetic Quantum Number (ml) Describes how an orbital is oriented in space about the nucleus (orbitals can exist at various different angles) s (1 orientation) p (3 orientations) px py pz dxy orbital dxz orbital dyz orbital dx2-y2 orbital dz2 orbital 4) The Spin Quantum Number (ms) An electron can spin like a top in 1 of 2 possible directions (clockwise and counter-clockwise) and is given a value of +1/2 or -1/2 Two electrons of opposite spins can occupy the same orbital An opposite pair of electrons spins is a stable arrangement and produces no magnetism of the substance A single, unpaired electron shows magnetism and can be affected by a magnetic field  Shell: Sublevels Orbitals per Orbitals per Electrons per Electrons per Principal (Orbital sublevel Principal Sublevel Principal Quantum Shapes) Quantum Quantum Number (n2) Number (2n2) Number (n) 1 s 1 1 2 2 2 s 1 4 2 8 p 3 6 3 s 1 9 2 18 p 3 6 d 5 10 4 s 1 16 2 32 p 3 6 d 5 10 f 7 14  Seatwork / Homework Read p.153-158 Answer p.159 #2-4