When you wished upon a star…. Makes no difference who you are…

Fireworks consists a mixture of metal elements, some salts and other compounds. When these are ignited, a certain colour or a spark effect is given off. What is an element? What is a compound? What are mixtures?

An introduction to Classification Elements, Compounds & Mixtures

Things to be covered in this topic Elements Compounds Mixtures Summary

Revision on matter Is this a matter  or non-matter ? SOUND?

What is a matter? Matter is anything that has mass and occupies space. Examples of matter Tables, books, cars, air Non-examples of matter Revision on matter All matter is made up of basic building blocks called elements.

What is an Element? The simplest form of matter An element is a pure substance which cannot be broken down into any simpler substances by chemical processes or by electricity

What is an Element? There are more than 110 elements discovered to date, of which 92 are found naturally on Earth and 17 are made artificially or man-made. Iron, Fe Sulphur, S Chlorine, Cl

What is an Element? Elements are made up of tiny particles called atoms. Eg. Atoms of one element are different from the atoms of another element. Gold Atoms Carbon Atoms

What is an Element? The 110 elements are classified according to their properties in a Periodic Table. Each element is represented by a chemical symbol in the Periodic Table. Each symbol is made up of one or two letters. The first letter is always a capital letter; the second letter (if any) is always in lower case. The letters can come from names of the element in other languages such as Arabic, Greek and Latin.

Chemical Symbols Why the need for special symbols for elements? Faster to use symbols than to write the whole name. Scientists from around the world use the same symbol for easy communication.

Write the chemical symbols for the following (write on the whiteboard) Sodium (Miss Cheryl)  Iron Oxygen Chlorine Hydrogen Revision on element

Classification of elements Classification of elements by states Elements can be classified by their physical states at room temperature. Eg elements can be classified as solids, liquids or gas.

Classifying Elements - Solids Examples of solid elements: Sodium Carbon Gold

Classifying Elements - Liquids Examples of liquid elements: Mercury Bromine

Classifying Elements - Gases Examples of gaseous elements: Chlorine Nitrogen Argon There are 11 gaseous elements in the periodic table.

Classification of elements Classification of elements as Metals and Non-metals Elements can be classified as metals and non-metals.

Classification of elements Metals Non-Metals

Give the names and chemical symbols of some common metal elements. Give the names and chemical symbols of some non-metal elements. Revision on elements

Classification of elements Classification of elements in the Periodic Table Elements have been arranged in the Periodic Table according to their properties. But.. Chotto Matte … How are the elements organised in the periodic table?

Elements in the same vertical column (called a group) have similar properties.

Elements in the same horizontal row (called a period) show a gradual change from metallic properties to non-metallic properties, from left to right across the Period.

Uses of elements The uses of an element is dependent on its properties. For example, hydrogen gas has the lowest density of all the gases. It was used to fill airships in the early 1900’s.

Uses of elements However, it is also highly flammable. In 1937, a disaster occurred when a German airship exploded, killing 36 people. Now, helium gas is used instead

Uses of Elements Aluminium is used to make airplane bodies Chlorine is used to kill bacteria in swimming pools

Uses of Elements Copper is used to make wires Gold is used to make jewellery and sculptures

Uses of Elements Helium is used to fill balloons. Hydrogen is used as fuel in rockets

Uses of Elements Mercury is used in thermometers. Silicon is used to make electronic parts.

What is a Compound? A compound is a substance that is made up of one or two elements chemically joined together. Although there are only a small number of elements, there are millions of compounds.

Formation of Compounds Compounds have different properties from the elements that are made of. Sodium + + Chlorine   Sodium Chloride

Formation of Compounds When elements combine directly to form a compound, heat or light is usually given out or taken in. oxygen hydrogen + chemical reaction (chemical change) water element element compound! mixture of hydrogen and oxygen gases mixing (physical change) mixture!

Formation of Compounds Compounds can be formed naturally. Example: Carbon + Oxygen  Carbon dioxide 2. Compounds can also be formed in the laboratories. I. Chemical reaction between elements. Iron + Oxygen  Iron Oxide (element) (element) (compound)

Formation of Compounds Chemical reaction between elements and compounds. Colourless Colourless Brown fumes Nitric Oxide + Oxygen  Nitrogen dioxide (compound) (element) (compound)

Formation of Compounds Chemical reaction between compounds. Black Colourless Copper (II) oxide + Sulphuric acid Copper (II) Sulphate + Water (compound) (compound) (compound) (compound)

Compounds Ask yourself! How do you think compounds can be separated? A chemical reaction using heat or electrolysis is required to separate compounds.

Decomposition of compounds A compound may be broken down into simpler substances using heat or electricity. This process is known as decomposition. The products are formed are either simpler compounds or the elements which make up the compound.

Breakdown a Compound Electrolysis of water into hydrogen and oxygen gas

MIXTURES

All substances Pure substances Mixtures Compounds Elements

What are Mixtures? Mixtures (impure substances) consisting of two or more substances which are not chemically joined together and can be easily separated by physical methods.

What are Mixtures? Examples of mixtures Air (a mixture of gaseous elements such as nitrogen, oxygen and the noble gases and other compounds like carbon dioxide) Mineral water (a mixture of water and dissolved minerals like calcium, sodium, potassium, magnesium) Bronze (a mixture of two elements, Copper metal and Tin metal. The substances which make up the mixture may be solids, liquids or gases.

Many things around us are mixtures and these include the food and drinks we consume Are you able to name more examples of mixtures? E.g. Carbonated drinks, Air, Milk, Coffee Examples of Mixtures S.Participate

Types of Mixtures Element-Element mixtures: Zinc and Iron Compound-Compound mixture: Sugar and water Element-Compound mixture: Zinc and water

Element-Element mixtures: Example 1: Alloys RECALL: An alloy is a mixture of metals with other elements. Steel is a mixture of 2 elements, Iron (metal) and Carbon (non-metal). Bronze is a mixture of 2 elements, Copper (metal) and Tin (metal). Brass is a mixture of 2 elements, Copper (metal) and Zinc (metal).

Compound-Compound mixture: Example 1: Sea Water / Salt Solution Seawater / Salt Solution is a mixture of compounds such as Sodium Chloride (salt) and Water. Example 2: Alcoholic Drinks / Ethanol Solution Alcoholic Drinks / Ethanol Solution is a mixture of compounds such as _______________ and _______________.

Element-Compound mixture: Example 1: Air Air is a mixture of elements (Oxygen, Nitrogen and other noble gases) and compounds (Carbon dioxide and water vapour).   Example 2: Iodine and Sodium Chloride The mixture of iodine (an element) and sodium chloride (a compound) can be easily separated by the physical method, filtration.  

Substances in a mixture can be mixed in any proportion (not fixed). A mixture has variable melting and boiling points. A mixture has the properties of the substances that make it up. A mixture can be separated into its components. Properties of Mixture

Comparison of Compounds and Mixtures