Quantum Mechanics and Configuration The Bohr Model 2: Quantum Mechanics and Configuration

C12-2-06 ELECTRON CONFIGURATION OUTCOME QUESTION(S): C12-2-06 ELECTRON CONFIGURATION Relate the electron configuration of an element to its valence electron(s) and its position on the Periodic Table. Include: quantum energy level, shapes, and orbitals. Write the electron configuration for a variety of atoms and ions using the 3 configuration laws. Include: shorthand notation and valence configuration Vocabulary & Concepts  Principal quantum number (n)

de Broglie (1924) – developed an equation that predicts wave qualities for all matter. If waves of light could contain photon-particles, could matter have wave properties? Suggests orbits are fixed because electrons (as a wave) could only move as strict standing wavelength

The famous “double-slit” experiment proved the “wave-particle duality” of matter (click the TV link below)

Think - trying to catch a frog in the dark with a flashlight… Problems: World is 3-dimensional Bohr’s math failed to explain all spectra Matter also has wave properties Heisenberg (1925) - it is impossible to know precisely the velocity and position of a particle at the same time – Heisenberg Uncertainty Principle Think - trying to catch a frog in the dark with a flashlight…

Schrödinger (1926) – developed a wave equation that describes the energies and behaviour of subatomic particles. Determines the probability of finding an electron in a 3-D volume of space around the nucleus. At this point, scientists couldn’t really figure matter out experimentally, so they turned to math and computers…

Each energy level's boundary is the area of electron location 90% of the time

principle quantum number (n) Bohr’s orbits are now called: principle quantum number (n) The (n) number indirectly describes the size and energy requirements of an orbit (electrons have more energy further out)

distance from the nucleus 2. Angular momentum (l) shape of orbital The probable location of every electron is now described by a set of 4 quantum numbers: This is a lot of detail – focus on the words not the letters (distance, shape, orientation, spin) QUANTUM NUMBERS Principal (n) distance from the nucleus 2. Angular momentum (l) shape of orbital 3. Magnetic (m) orientation in 3D space 4. Spin momentum (s) spin of the election

Principal (n) - distance Number of shapes (l) in each level equals the principal quantum number (n) for that level NUCLEUS n = 1 s n = 2 s p n = 3 s p d Like a stadium, the further from the stage (nucleus) the more “sections” of seating for people (electrons)

S – sphere P – dumbbell D – clover F - ?? 2. Angular momentum (l) - shape Higher quantum numbers (n) contain many sections of probable electron location – shapes (l) There are four shapes appearing in this order: S – sphere P – dumbbell D – clover F - ?? These shapes represent probable locations for finding electrons around the nucleus

3. Magnetic (m) – orientation Shapes (l) can be made of multiple orbitals (m) that occupy the axes of 3D space (x, y, z) “s” shape (sphere) – 1 orbital orientations “p” shape (dumbbell) – 3 orbital orientations “d” shape (clover) – 5 orbital orientations “f” shape (indeterminate) – 7 orbital orientations Think about how many ways each shape can be represented in space – the next picture will help…

“s” shape – 1 orbital orientations (just one – in the middle of x, y and z axis) “p” shape – 3 orbital orientations (along the x, the y or the z axis) “d” shape – 5 orbital orientations (along x and y, xz, yz…) “f” shape – 7 orbital orientations (along the …I don’t know what that is)

Notice the distance, shape, orientation OLD way NEW way Notice the distance, shape, orientation

4. Spin momentum (s) – spin Each orbital holds two spinning electrons (s) Level Shapes orbitals e- capacity 1 s 1 = 1 2 s,p 1+3 = 4 8 3 s,p,d 1+3+5 = 9 18 4 s,p,d,f 1+3+5+7 = 16 32 n n types n2 2n2

1s2 2s2 2p6 3s2 3p6 3d10 n = 3 n = 2 n = 1 2e- 8e- 18e- 2e- 8e- 8e- OLD way NEW way

C12-2-06 ELECTRON CONFIGURATION CAN YOU / HAVE YOU? C12-2-06 ELECTRON CONFIGURATION Relate the electron configuration of an element to its valence electron(s) and its position on the Periodic Table. Include: quantum energy level, shapes, and orbitals. Write the electron configuration for a variety of atoms and ions using the 3 configuration laws. Include: shorthand notation and valence configuration Vocabulary & Concepts  Principal quantum number (n)