4-4 A New Approach to 4-4 A New Approach to the Atomthe Atom

ReviewReview Energy is quantized ( found in Energy is quantized ( found in

specific amounts)specific amounts) Electrons have wavelike behaviorElectrons have wavelike behavior Impossible to know electron position Impossible to know electron position

and momentum.and momentum. Can predict the probability of Can predict the probability of

electron locationelectron location Called the Quantum-mechanical modelCalled the Quantum-mechanical model

Probability and OrbitalProbability and Orbital An orbital is the region where a given An orbital is the region where a given

electron is likely found. electron is likely found.

The density of an electron cloud is The density of an electron cloud is called the electron density.called the electron density. Higher density – more likely to find electronHigher density – more likely to find electron Lower density – less likely to find electronLower density – less likely to find electron

Each orbital has specific sizes and Each orbital has specific sizes and shapes.  shapes.  s, p, ds, p, d, and , and f. f.  The shape of the cloud is where The shape of the cloud is where

electrons are likely to be found 90% of electrons are likely to be found 90% of the time.the time.

S orbitalS orbital

P orbital- see figure 4-26 in P orbital- see figure 4-26 in bookbook

d orbital – see figure 4-27 in d orbital – see figure 4-27 in bookbook

Orbitals and EnergyOrbitals and Energy The The energy levelsenergy levels are given the initial are given the initial n, n,

called the called the principle quantum numberprinciple quantum number As the energy of an electron increases so As the energy of an electron increases so

does its principle quantum numberdoes its principle quantum number n =1 has only one subleveln =1 has only one sublevel n = 2 has 2 sublevels, 2s and 2pn = 2 has 2 sublevels, 2s and 2p n = 3 has three sublevels, 3s, 3p, and 3dn = 3 has three sublevels, 3s, 3p, and 3d 4 sublevels, 4s, 4p, 4d, and 4f4 sublevels, 4s, 4p, 4d, and 4f

* Note 3d fills before 4p, this is what is found in nature. The energy levels get closer together.

Each of the sublevels orbits can Each of the sublevels orbits can contain up to two electrons that contain up to two electrons that travel in opposite directions or spins travel in opposite directions or spins

Electron SpinElectron Spin The spin of an electron is either The spin of an electron is either

clockwise or counter clockwiseclockwise or counter clockwise These spins create magnetic fieldsThese spins create magnetic fields

Summary of Energy Levels, Summary of Energy Levels, Sublevels, and OrbitalsSublevels, and Orbitals

Principal Principal Energy LevelEnergy Level

SublevelsSublevels OrbitalsOrbitals

n = 1 n = 1 1s1s 1s (one)1s (one)

n = 2n = 2 2s, 2p2s, 2p 2s (one) + 2p 2s (one) + 2p (three)(three)

n = 3n = 3 3s, 3p, 3d3s, 3p, 3d 3s(one) + 3p(three)3s(one) + 3p(three)+3d(five)+3d(five)

n = 4n = 4 4s, 4p, 4d, 4f4s, 4p, 4d, 4f 4s(one)+4p(three)4s(one)+4p(three)+4d(five)+4f(seven)+4d(five)+4f(seven)