Answer the following:

Country :

Province :

City :

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Arrangement of Electrons in Atoms

Electrons in atoms are arranged as

LEVELS (n)

SUBLEVELS (l)

ORBITALS (ml)

Quantum Mechanicshttp://www.meta-synthesis.com/webbook/30_timeline/310px-Bohr-atom-PAR.svg.png

Better than any previous model, quantum mechanics does explain how the atom behaves.

Quantum mechanics treats electrons not as particles, but more as waves (like light waves) which can gain or lose energy.

But they can’t gain or lose just any amount of energy. They gain or lose a “quantum” of energy.

A quantum is just an amount of energy that the electron needs to gain (or lose) to move to the next energy level.In this case it is losing the energy and dropping a level.

Energy Levelshttp://www.chem4kids.com/files/art/elem_pertable2.gif

Quantum mechanics has a principal quantum number. It is represented by a little n. It represents the “energy level” similar to Bohr’s model. n=1 describes the first energy

level

n=2 describes the second energy level

Etc.

Each energy level represents a period or row on the periodic table. It’s amazing how all this stuff just “fits” together.

Red n = 1Orange n = 2Yellow n = 3Green n = 4Blue n = 5Indigo n = 6Violet n = 7

Sub-levels = Specific Atomic Orbitals

Each energy level has 1 or more “sub-levels” which describe the specific “atomic orbitals” for that level. n = 1 has 1 sub-level (the “s” orbital)

n = 2 has 2 sub-levels (“s” and “p”)

n = 3 has 3 sub-levels (“s”, “p” and “d”)

n = 4 has 4 sub-levels (“s”, “p”, “d” and “f”)

There are 4 types of atomic orbitals: s, p, d and f

Each of these sub-levels represent the blocks on the periodic table.

Blue = s block

Orbitalshttp://media-2.web.britannica.com/eb-media/54/3254-004-AEC1FB42.gif

http://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/D_orbitals.svg/744px-D_orbitals.svg.png

In the s block, electrons are going into s orbitals.

In the p block, the s orbitals are full. New electrons are going into the p orbitals.

In the d block, the s and p orbitals are full. New electrons are going into the d orbitals.

What about the f block?

s p d

Table:

s = 2 p = 6 d = 10 f = 14

Complete the chart in your notes as we discuss this.

The first level (n=1) has an s orbital. It has only 1. There are no other orbitals in the first energy level.

We call this orbital the 1s orbital.

Energy Level

Sub-levels

Total Orbitals Total Electrons

Total Electrons per Level

n = 1 s 1 (1s orbital) 2 2

n = 2 sp

1 (2s orbital)3 (2p orbitals)

26

8

n = 3 spd

1 (3s orbital)3 (3p orbitals)5 (3d orbitals)

2610

18

n = 4 spdf

1 (4s orbital)3 (4p orbitals)5 (4d orbitals)7 (4f orbitals)

261014

32

Electronic Configuration

The electron configuration is the specific way in which the atomic orbitals are filled.

It tells where all electrons “live.”

Rules for Electronic Configuration

The Aufbau Principle requires that the electrons occupy the

lowest possible energy level before filling up the next.

Pauli’s Exclusion Principle posits that no two electrons can

have the same set of four quantum number; the spin quantum

number limits the number of electrons in an orbital to a

maximum of two.

Hund’s Rule requires that the electrons fill the orbitals in a

subshell one by one, before pairing the electrons in an orbital

spin in opposite directions.

Electron Configurations

2p4

Energy Level

Sublevel

Number of electrons in

the sublevel

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6

6s2 4f14… etc.

Practice

1. Ne – 10

2. Ca – 20

3. Fe- 26