Transcript Slide 1
The Quantum Model of the Atom 4.2 Light and Electrons • Louis de Broglie suggested that e- in fixed orbitals (like Bohr suggested) behave with wave like properties. • He hypothesized that electrons also have dual particle-wave nature. Electrons as waves • Can be diffracted – wave passes by the edge or through a small opening • Interference – waves pass over each other • Heisenberg uncertainty principle – it is impossible to determine simultaneously both the position and velocity of an e- or any other particle. Schrödinger • Schrödinger wave equation – probability of finding an electron in a certain orbital • Schrö and Heis = foundation for … • Quantum Theory – describes mathematically the wave properties of electrons and other very small particles. Quantum Numbers • Orbital – 3-d region around the nucleus that indicates the probable local of an e• We can learn more than just what orbital e-s are in… • Quantum Numbers – specify the properties of atomic orbitals and the properties of e- in orbitals • Like seats at a concert Principal Quantum Number, n • PQN–the main E level occupied by the e• n values are positive • As n increases so does the distance from the nucleus • Angular momentum quantum number, l – the shape of the orbital • Values can be 0 and any # lower than what n = (if n=3, l can be 0, 1, and 2) Magnetic Quantum Number, m • MQN = the orientation of the orbital around the nucleus • Values can be whole numbers, from -l, 0 to +l • If l = 2, m can be -2, -1, 0, 1, 2 The Spin Quantum Number • SQN = has only 2 possible values (+1/2, -1/2) which indicate the two fundamental spin states of an electron in an orbital • A single orbital can hold a max of 2 electrons, but they must have opposite spin states.