7th Chemistry - Atoms, Particles and Numbers

St. George's College

Subject: 7th CHEMISTRY

Class: Atoms, Numbers and

Teacher's notes

Objectives

Vocabulary Link and Learn

Properties Date: March 25th

Prepared by

2009

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7th Beethoven ‐ Branches of Chemistry Name

Oral Intervention

Coin

Chocolate

Ariana Gabriel Andrea Abraham Giacomo Fabiana Sinead Liliam Francesca Rodrigo Andres Stefano Jean Pierre Diego Rodrigo Luis Andrea Sebastián Ivanna Camila Carlos Aarón Paola Enrique Alessandra Irma Sophia Naomi Kiara Christopher

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7th Mozart‐ Branches of Chemistry Name

Oral Intervention

Coin

Chocolate

Nicole Luis Luciana Antonella Valeria Ch. Valeria C. Analucía Camila Franco Ramiro Sara Alicia José Luis Sergio Roberto Giancarlo Fiorella Gabriela Steffano Javier

Roberto R. Diego Luis Fernando Sebastián Julio Sherley César Vilma Alessandra V.

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INSIDE THE ATOM We already know that the components of atoms are: Neutrons

Protons

Electrons

Particle Symbol Charge

Mass (Kg)

Size (m)

Neutron

n0

0

1.67495 x 10‐27 10‐15

Proton

p+

+1

1.67265 x 10‐27 10‐15

Electron

e‐

‐1

9.1095 x 10‐31 10‐18

0

Variable

ATOM

10‐10

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QUANTUM MECHANICS

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ENERGY LEVELS • Electrons move around the nucleus (negative charge around positive charge).

• Even though it looks as if this movement is disorganized, in fact there is a strict organization of the electrons.

• Electrons move around the nucleus packed in Energy Levels.

• Energy levels are the "layers" around the nucleus where electrons are found in motion.

• These energy levels are called Electron shells.

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ELECTRON SHELLS

proton

neutron

e‐ e‐

e‐

electron

e‐ e‐

e‐

How many electron shells are there in the graphic?

How many electrons are there in the graphic?

What is the atomic number of the atom in the graphic?

What element is represented in the graphic?

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Rules to fill up the Electron Shells 1. The first electron shell, the closest to the nucleus can hold up to 2 electrons.

2. The other electron shells can hold many more electrons.

3. The last electron shell can only hold up to 8 electrons, this is called the Octet Rule.

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Filling up the Electron Shells

proton

Represent the following atoms:

neutron

An Atom with 11 protons e‐

e‐

electron

e‐

e‐

e‐ e

e‐

e‐ ‐

e‐

e‐ e

‐

e‐

An Atom with 23 electrons

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Filling up the Electron Shells

proton

Represent the following atoms:

neutron e‐

An Atom with 11 protons e‐

electron

e‐ e‐

e‐

e

e‐

‐

e‐ e‐

e‐ e‐

e‐

An Atom with 23 electrons

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The Current Atomic Model

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QUANTUM MECHANICS UNCERTAINTY PRINCIPLE ‐ Werner Heisenberg It is not possible to simultaneously determine the speed and position of the electron accurately.

ATOMIC ORBITAL: region in space where it is more probable to find the electron.

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QUANTUM NUMBERS: are mathematical expressions used to describe the energies of atoms, angular moment, electron spin, etc. It is used to determine the distribution of electrons in the atomic orbitals.

Quantum Number

Function

n principal quantum number Energy Level Determines the energy level where the e‐ is located. The higher n value, the farthest the e‐ from the nucleus.

Values 1,2,3,4,5,6,7

Shape of the atomic orbital Energy Sublevel

0 < l < n‐1

m magnetic quantum number Space representation of the It represents the space orientation of atomic orbitals the orbitals in the energy sublevels.

l < m < l‐1

s spin quantum number It describes the spin orientation of the e‐.

‐½, +½

l secondary quantum number (azimuthal or orbital) Determines the energy associated with the e‐ movement around the nucleus; it indicates the energy sublevel.

Shows the electron spin

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Shapes of Atomic Orbitals l secondary quantum number (azimuthal or orbital)

Orbital s: Sphere symmetry.

The size of orbital "s" increases when the principal quantic number increases too.

Orbital p: lobe‐shaped orbitals.

There are 3 types of "p" orbitals, differing by their orientation.

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Orbital d: third sublevel of energy.

There are 5 types of "d" orbitals, with different space orientations.

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Orbital f: complex orientations.

There are 7 types of "f" orbitals, with different space orientations.

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Let's check an example on how to fill the electron shells.

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ATOMIC PROPERTIES

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ATOMIC NUMBER • Each element has an Atomic Number, and is determined by the number of protons.

• All the atoms of a particular element have the same number of protons.

Atomic Number = Number of Protons

MASS NUMBER • The mass of each element is determined by the number of protons and neutrons.

• The mass of electrons is so minute that it is not considered in the calculations of the atomic mass.

Atomic Mass = Number of Protons + Number of Neutrons 20

ISOTOPES • Some elements are made up of atoms with different masses.

• For atomic masses, the number of protons always remains the same.

• Isotopes are elements with a different number of neutrons. e‐

e‐

e

e‐

‐

e‐

e‐

e

e‐

‐

e‐

e‐

e‐

e‐

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The Nuclei of the three isotopes of Hydrogen Protium

Tritium

+

+

1 proton

1 proton 1 neutron

Deuterium

+ 1 proton 2 neutrons

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23

24

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27

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29

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Resources Used Slide (Group)

Resource

Description

Origin

G1 ‐ 2

Image

Beethoven

http://bit.ly/Q7ggk

G1 ‐ 3

Image

Mozart

http://bit.ly/18LkW6

Black Hole Sand falling Eye of hurricane

http://bit.ly/aFjIf http://bit.ly/KPlLQ http://bit.ly/JrxKK

Wooden Balls Elements

http://bit.ly/JCInm http://bit.ly/PvvMp

G1 ‐ 4 Images

G1 ‐ 6

Images

G1 ‐ 8 Images

JJ Thomson http://bit.ly/Qpn0G Cathode Ray Tube http://bit.ly/aTsuR Raisins in a Pudding http://bit.ly/yuNB

G1 ‐ 10 Animation

Rutherford's Model http://bit.ly/11YT09

G1 ‐ 11 Animation

Bohr's Model

http://bit.ly/13Q7PT

G1 ‐ 12 Animation

Plasma

Unknown

Chemistry

http://bit.ly/18R0M

Atom of Helium

http://bit.ly/JtON

Chemistry

http://bit.ly/18R0M

G1 ‐ 13,14,15,16

Activities

G1 ‐ 17 Animation G2 ‐ 7,8,9 Activities

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Teacher's Notes This class has been designed to cover the topics of Particulate Nature of Matter from Monday March 16th till Friday March 20th.

For further knowledge about this topic: 1. Conduct a thorough search under the topic: Particulate Nature of Matter on the Web, books and magazines.

2. If findings are not specific, ask your teacher for suggestions.

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Objectives • Describe and analyze the nature and components of Matter.

• Identify and describe the experiments that lead to the different models of atomic theory.

Note: All, or most, of the objectives will be covered during class time, however the student must be responsible for those objectives not covered or concluded.

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Vocabulary • • • • • • •

Matter: Atom: Nucleus: Electronic Cloud: Proton: Neutron: Electron:

Note: Most of the vocabulary words will be covered during class time, however the student must be responsible for those words not covered or concluded.

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Link and Learn You can visit the following websites to improve your understanding on the present topic: • • • • • •

http://bit.ly/PvvMp http://bit.ly/KCmja www.sanjorge.edu.pe http://science‐learning2009.wikispaces.com http://learningandscience.blogspot.com http://libraryatstgeorge.blogspot.com

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Prepared by

Gerardo LAZARO Science Lead Teacher Email: glazaro@sanjorge.edu.pe Wiki: http://science‐learning.wikispaces.com Blog: http://learningandscience.blogspot.com Twitter: http://twitter.com/glazaro

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The correct statement is ...

1. Atoms are made up of electrons, neutrons and protons.

2. Atoms do not contain electrons but they do contain protons and neutrons.

3. Atoms never contain neutrons Click here to go back

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The correct statement is ...

1.

Electrons are positively charged

2. Neutrons do not weigh anything

3. Protons are found inside the nucleus Click here to go back

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The structure of an atom

Nucleus

Electrons

{

Neutrons

Protons Click here to go back

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Attachments

7th Chemistry ­ Reading 1 ­ Branches of Chemistry ­ Supergoo to the Rescue.docx 7th Chemistry ­ Reading 1 ­ Branches of Chemistry ­ Graphene's Superstrength.docx 7th Chemistry ­ Reading 1 ­ Branches of Chemistry ­ Meteorites may have sparked life on earth.docx 7th Chemistry ­ Reading 1 ­ Branches of Chemistry ­ Plastic munching microbes.docx