Electron Filling Power Point

Electron Configuration and the Periodic Table Book Reference: Section 3, Chapter 3

The Puzzle of the Atom Protons and electrons are attracted to each other because of opposite charges Electrically charged particles moving in a curved path give off energy Despite these facts, atoms don’t collapse

The electron  What

is an electron?  How does it behave or function?  What evidence do we have for the existence of the electron?

Discovery of the Electron In 1897, J.J. Thomson used a cathode ray tube to deduce the presence of a negatively charged particle.

Cathode ray tubes pass electricity through a gas that is contained at a very low pressure.

Wave-Particle Duality JJ Thomson won the Nobel prize for describing the electron as a particle. His son, George Thomson won the Nobel prize for describing the wave-like nature of the electron. The electron is a particle!

The electron is an energy wave!

The Wave-like Electron The electron propagates through space as an energy wave. To understand the atom, one must understand the behavior of electromagnetic waves.

Louis deBroglie

Electromagnetic radiation propagates through space as a wave moving at the speed of light.

c = νλ C = speed of light, a constant (3.00 x 108 m/s) ν = frequency, in units of hertz (hz, sec-1) λ = wavelength, in meters

Types of electromagnetic radiation:

The energy (E ) of electromagnetic radiation is directly proportional to the frequency (ν) of the radiation.

E = hν

E = Energy, in units of Joules (kg·m2/s2) h = Planck’s constant (6.626 x 10-34 J·s) ν = frequency, in units of hertz (hz, sec-1)

Long Wavelength = Low Frequency = Low ENERGY Short Wavelength = High Frequency = High ENERGY

Wavelength Table

Spectroscopic analysis of the visible spectrum… …produces all of the colors in a continuous spectrum

Spectroscopic analysis of the hydrogen spectrum… …produces a “bright line” spectrum

Absorption and Emission of Energy

Electron Orbitals  How

are electrons arranged around the nucleus of an atom?  What do these arrangements look like?

Electron Orbitals  One

way to think about orbitals is to think of them as rooms within a house.  The house is all of the electrons in an atom, with the rooms being where the electrons are located.  In the quantum model, the rooms are represented with letters.

Electron Energy Level (Shell) Generally symbolized by n, it denotes the probable distance of the electron from the nucleus. Number of electrons that can fit in a shell:

2n2

Energy Levels, Sublevels, Electrons

Energy Level (n )

Sublevels in main energy level (n sublevels)

Number of orbitals per sublevel

Number of Electrons per sublevel

Number of electrons per main energy level (2n2)

1

S

1

2

2

2

S p

1 3

2 6

8

3

S P D

1 3 5

2 6 10

18

4

S P D F

1 3 5 7

2 6 10 14

32

The s orbital has a spherical shape centered around the origin of the three axes in space. The s orbital can hold 2 electrons

s orbital shape

P orbital shape

There are three dumbbell-shaped p orbitals in each energy level above n = 1, each assigned to its own axis (x, y and z) in space. The p orbitals can hold up to 6 electrons

Things get a bit more complicated with the five d d orbital shapes orbitals that are found in the d sublevels beginning with n = 3. To remember the shapes, think of “double dumbells” …and a “dumbell with a donut”! The d orbitals can hold 10 electrons

Shape of f orbitals

The f orbitals can hold 14 electrons.

Electron Orbitals  One

way to think about orbitals is to think of them as rooms within a house.  The house is all of the electrons in an atom, with the rooms being where the electrons are located.  In the quantum model, the rooms are represented with letters.

Electron Configuration 



Remember to start at the beginning(1s) of each arrow, and then follow it all of the way to the end, filling in the sublevels that it passes through. In other words, the order for filling in the sublevels becomes; 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d,7p. Note: the diagram in your book is different, but the process is the same.

How to Write Electron Configurations 1. 2.

3.

Find the number of electrons in your element Use the orbital filling diagram(top of page 98 in your book) to place electrons until you’ve reached the total number of electrons for your element. Check to make sure the number of electrons used equals the number needed to place.

Forms of Electron Configuration  Use

manganese, Mn, and give the following information  Electron

configuration  Orbital Notation  Noble gas notation

Orbital filling table

Element Identification and Electron Configuration  An

element has the following electron configuration: 1s22s22p63s23p5  What is the symbol of the element?  What is the highest energy level occupied by an electron?  How many electrons are in that energy level?  What is the orbital notation for this element?  What is the Noble gas configuration for this element?

Exit Questions  What

evidence is there for the existence of electrons?  What evidence exists for the existence of electrons in discrete regions around the nucleus?  Describe the process for giving the electron configuration for potassium(K).