EMR exhibits particle (photon) and wave (ν, λ, Amp) properties and all energy is transferred in quantum. Elements have unique emission spectra because of a different number of protons and electrons. Different elements have different orbital jumps to make, and have different quanta energy requirements. Results in different frequencies of radiation being absorbed and emitted by different elements.

Absorption spectrum – portion of visible light absorbed by an element – heating up. Emission spectrum – portion of visible light emitted by that element – cooling down.

Quantum Mechanic Theory and the Atom Structure

Explain the problems with the Bohr model. Understand the difference between energy level, sublevel, and orbital. Be able to explain the basic structure of electron arrangement.

de Broglie (1924) - electrons also wave-like. Electrons can only move at certain wavelengths around the nucleus – helps explains why energy absorbed in specific quantized values.

Problems - Bohr model is 1-D model. - e - also have wave-particle duality. Heisenberg (1927) - it is impossible to know precisely the velocity and position of a particle at the same time – Heisenberg Uncertainty Principle

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.

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

Bohr’s orbits called principal energy levels, or quantum numbers (n). The principal quantum number (n) indirectly describes the size and energy of an orbit.

Principle energy levels contain many places of probable electron location – sublevels. Sublevels vary in terms size, shape and orientation in space. There are four types that appear in this order: spd f Sublevels exist as different orbital orientations in 3D space.

n = 1 n = 2 n = 3

number of sublevels per energy level (n) equals the principal quantum number for the level. n = 1 – contains one sublevel: 1s n = 3 – contains three sublevels: 3s, 3p, and 3d. spd

s sublevel (sphere) – 1 orbital orientation present.

p sublevel (dumbell) – 3 orbital orientations.

d sublevel (cloverleaf) – 5 orbital orientations. f sublevel (indeterminate) – 7 orbital orientations.

1s2s 2p3s 3p 3d n = 1 n = 2 n = 3

Energy Level SublevelsTotal Orbitals 1s1s1s 2s,p1s+3p = 4 3s,p,d1s+3p+5d = 9 4s,p,d,f1s+3p+5d+7f = 16 nn typesn2n2