Quantum Model of the Atom


The Bohr Model of the atom was incorrect Electrons do not orbit the nucleus


In the modern (quantum) model of the atom, electrons are found in regions of space called orbitals

Orbitals are clouds of probability where electrons are most likely to be found

The shape of these clouds is the result of plotting the solutions to very complicated mathematical equations

We will study 3 types: s, p, and d


There are 7 periods on the periodic table Each period represents the number of

energy levels in an atom Each energy level is represented by “n”

Structure of the Quantum Atom Structure of the electron cloud

Principle energy levels (n) Obtained from the Periodic Table Are whole numbers: 1, 2, 3, 4….

Sublevels s, p, d, f

Orbitals – a MAX of two electrons are allowed in each orbital for each value of n:

s has one obital p has three d has 5

Spin Obtained from the Periodic Table


“s” orbitalsSpherically shaped There is one “s” orbital for each energy level


This is the probability diagram of an “s” orbital

n = 1This is a “1 s” orbital

n = 2This is a “2 s” orbital


“p” orbitalsDumbbell shaped, with three different

orientations in spaceStarting with n = 2, there are THREE “p”

orbitals, px, py, pz for each energy level


“d” orbitalsDumbbell shapedStarting with n=3, there are 5 “d” orbitals


How electrons fill their orbitalsPauli Exclusion PrincipleEach orbital can hold a maximum of TWO

ELECTRONSAufbau Principle Electrons fill orbitals that have the

LOWEST ENERGY FIRST

The Quantum Model of the Atom

Filling sequence:

1s<2s<2p<3s<3p<4s<3d

Each orbital can hold a maximum of 2 electrons


Example:HydrogenHas one electronThe first energy level to fill is the 1s orbitalThe one electron will fill in this orbital

1s1

1s1Energy

Level

Orbital Number of Electrons in Orbital


Electron ConfigurationsThe arrangement of electrons in an atomFilling pattern:

1s<2s<2p<3s<3p<4s<3d……..

Or use the following:


Filling Pattern 1s<2s<2p<3s<3p<4s<3d……..

Model of the atom with s and p orbitals

Quantum Model of the Atom

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