Chemistry Core Lesson 1

• http://www.privatehand.com/flash/elements.html• All must • Know that all substances are made of atoms. • know and define the term element.• be able to name several elements• be able to find several elements in the Periodic

Table .• Most should• Know the layout of the Periodic Table• Be able to use chemical symbols.•http://clipbank/espresso/clipbank/servlet/link?macro=setresource&template=vid&resourceID=1618&taxonomyNodeID=731

Chemistry Core

• What is an element?• An element is a single pure substance

which cannot be broken down into anything simpler.

• An element is made of identical atoms.• What is an atom?• Atoms are small spheres.• The atoms of one element are different

from the atoms of every other element.

Where are all elements listed?

• In the Periodic Table – a list of all known elements.

• Why use symbols?• It’s simpler than writing long names!• Symbols are known all over the world even in

different languages.• E.g. S is always sulphur, even though the Japanese for

sulphur is iwo, the Spanish is azufre and the French is soufre

• Rules For Symbols:• Either one capital letter e.g. C carbon• OR one capital letter and one lower case letter• E.g. Zn zinc

The Periodic Table

• The Periodic Table is divided up:• Into metal and non metals – where?• Metals and non metals are separated by a

zig zag starting to the LEFT of Boron – where is this?

• Into Groups – where and why?• Groups are VERTICAL COLUMNS of similar

elements.• Into Periods where?• Periods are HORIZONTAL ROWS.

Chemistry and Our Earth

Interactive Periodic Table

• http://www.absorblearning.com/media/attachment.action?quick=tf&att=2108

• http://www.bbc.co.uk/learningzone/clips/groups-and-periods-in-the-periodic-table/10623.html

Structure of the Atom

• All must • know that atoms are made up of smaller sub

atomic particles.• know the mass, charge and position in the atom

of protons, neutrons and electrons and the charge on an atom.

• Most • should be able to use element symbols in the

Periodic Table to work out the numbers of sub atomic particles in atoms of any element

• Work out the electron arrangement for any element for the first 20 elements in the Periodic Table.

Atomic Structure

• http://clipbank/espresso/clipbank/servlet/link?macro=setresource&template=vid&resourceID=3495&taxonomyNodeID=731

1. Atoms have a small central nucleus containing protons and neutrons

2. Electrons orbit the nucleus3. Protons, neutrons and electrons have

different masses and charges

Structure of an Atom

Structure of an Atoms

Atomic structure

Atomic Structure

Atomic structure

Atomic Structure

1. The atomic number is the number of protons in the nucleus

2. In an atom, the number of electrons always equals the number of protons

3. Atoms do not have an overall electrical charge

Atomic number

Atomic Number

Atomic number

Atomic Number

1. The mass number is the total number of protons and neutrons in an atom

2. The number of neutrons can be calculated by subtracting the atomic number from the mass number

Mass number

Mass Number

Mass number

Mass Number

Calculations

Calculations

Electron arrangements

• Electrons move around the outside of the atom in an ‘electron cloud.’

• In the cloud are shells or energy levels where electrons have similar energy.

• Electron shells fill from the nucleus out.• Each shell holds a maximum number of

electrons.• When it is full the next shell out starts to

fill.• http://www.btinternet.com/~chemistry.diagrams/electron_adding.htm

• http://www.footprints-science.co.uk/flash/periodic.swf

What is the Electron Cloud Model?

Electron Arrangement

• http://clipbank/espresso/clipbank/servlet/link?macro=setresource&template=vid&resourceID=2056&taxonomyNodeID=731

• 1st shell = up to 2 electrons (nearest to the nucleus)

• 2nd shell up to 8 electrons• 3rd and subsequent shells APPEAR full at 8

electrons.

Electron Arrangement

• Work out the electron arrangement for the following:

• Li• Na• K• F• Cl• He • Ne• Ar

Electron Arrangement

• Elements in the same GROUP of the Periodic Table have the SAME number of electrons in their outer electron shell.

• How does this affect the properties of the elements?

• Some groups have names.• E.g. Group 1 contains the Alkali Metals

The Alkali Metals

• Physical Properties• http://www.rsc.org/Education/Teachers/Res

ources/Practical-Chemistry/video-clips/physical-properties-of-group-1-elements.asp

• Chemical Properties• Reaction with Water• Burning in Oxygen• Word and Formula Equations

Reaction with Water

Test Li Na K

Appearance

Does it float?

Does it fizz

Does it melt?

Does the gas ignite on its own?Flame colour?

Does it dissolve?

Colour of UI solution?

Conclusion?Elements in the same group of the Periodic Table have similar reactions because they have the same number of electrons in their outer shell.

Alkali Metals + Water

• http://clipbank/espresso/clipbank/servlet/link?macro=setresource&template=vid&resourceID=1503&taxonomyNodeID=735

• http://www.bbc.co.uk/learningzone/clips/alkali-metals/4407.html

• http://www.rsc.org/Education/Teachers/Resources/Practical-Chemistry/video-clips/caesium-with-water-longer.asp

• http://www.rsc.org/Education/Teachers/Resources/Practical-Chemistry/video-clips/rubidium-with-water-longer.asp

Reaction with oxygen

Gas jar

Burning metal

Heat the metal on the burning spoon.Plunge into gas jar of oxygen as shown.Record observations.http://clipbank/espresso/clipbank/servlet/link?template=vid&macro=setResource&resourceID=1489

Equations for the Reactions

• Example equations:• All group 1 elements behave in the same way so

have the same equations.• Sodium + oxygen sodium oxide• 4Na +O2 2Na2O

• Potassium + water potassium hydroxide + hydrogen

• 2K +2H2O 2KOH + H2

• http://www.chemistryhelp.net/basic-chemistry/word-equations

Noble GasesGroup 8 or 0Full outer electron shells.Do not form compounds.Uses reflect lack of reactivity.e.g. Argon in light bulbs prevents metal filament from burning.Do glow when electric current is forced through gas at low pressure.

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Unit 1: Chemistry and Our Earth

Equations

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Reactants and products

The starting substances used in a reaction are reactants.

The new substances formed in a reaction are products.

In a chemical reaction, one or more new substances

are formed.

The arrow means change into. In a chemical reaction, all the reactants change into the products.

reactants products

It is difficult to reverse a chemical reaction and change the products back into the reactants.

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What is a symbol equation?

A symbol equation uses the formulae of the reactants and products to show what happens in a chemical reaction.

This equation shows that one atom of sulfur (S) reacts with one molecule of oxygen (O2) to make one molecule of sulfur dioxide (SO2).

A symbol equation must be balanced to give the correct ratio of reactants and products.

+ S O2 SO2

+

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Balancing equations activity

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Symbol equations – balanced or not?

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Interactive Equation Balancing

• http://www.files.chem.vt.edu/RVGS/ACT/notes/scripts/bal_eq1.html

• http://education.jlab.org/elementbalancing/index.html

• http://funbasedlearning.com/chemistry/chemBalancer/default.htm

What is a chemical reaction?

• All must know that elements react when atoms join with other atoms to form compounds.

• Most should know how atoms combine and the names given to different types of bonding.

• Some could EXPLAIN how bonding occurs in different types of materials.

Reaction with chlorine

Gas jar

Burning metal

Heat the metal on the burning spoon.Plunge into gas jar of chlorine as shown.Record observations.http://www.youtube.com/watch?v=2mzDwgyk6QM

Chemical Reaction

• Takes place by• GIVING• TAKING• Or SHARING electrons.

Metal + Non metal

• Metals GIVE electrons to non metals.• Atoms become charged IONS.• These attract each other.• http://www.absorblearning.com/media/attac

hment.action?quick=sn&att=2052

1. An ionic bond is formed when a metal atom and a non-metal atom combine

2. The metal atom donates an electron to the non-metal atom

3. The metal atom becomes a positively charged ion, the non-metal atom becomes a negatively charged ion

4. The positive ion attracts the negative ion – an ionic bond

Ionic Bonding

Ionic Bonding

Ionic Bonding

Ionic Bonding

Ionic Bonding

Ionic Bonding

Ionic bonding

Ionic Bonding

IONIC BONDbond formed between

two ions by the transfer of electrons

1). Ionic bond – electron from Na is transferred to Cl, this causes a charge imbalance in each atom. The Na becomes (Na+) and the Cl becomes (Cl-), charged particles or ions.

COVALENT BONDbond formed by the sharing of electrons

http://www.absorblearning.com/media/attachment.action?quick=sw&att=2070

Non metal +Non metal - Element

Non metal atoms SHARE ELECTRONS to gain FULL OUTER SHELLS.e.g. Cl2

Shared pair of electrons = covalent bond.

Non metal + Non metal - Compound

Hydrogen chloride formation

Shared pair of electrons = covalent bond

Molecules of Covalent Materials

Summary

• http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/rocks/atomsact.shtml