Characteristics of Substances

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Characteristics of Substances

• Elements, compounds, mixtures

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Atoms
Smallest piece
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Elements
Red block
Blue block
Each type of Atom is called an Element
LEGO WORLD
Different colours ,sizes and shapes Different properties
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• Elements are substances made up of only one type
  of atom.
• Example

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MoleculesA molecule is made up of two or more
atoms chemically combined.
O
H
H
Water (H2O)
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Chemical Reaction

• Element or Molecules combining together gt
  Chemical Reaction

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Aristotle's Elements
Earth Air Fire Water
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What is an Element ?

• Everything in the Universe is made from Elements
• There are over 100 elements
• The most common element in the Universe is
  Hydrogen
• The Term Element was introduced by an Irish
  scientist Robert Boyle
• Simple Substance

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Element

• An Element is a substance that cannot be split up
  into simpler substances by chemical means.

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Common Elements
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Oxygen Most abundant Element in Earths Crust
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What is this ?
Element Percentage
Oxygen 65
Carbon 18
Hydrogen 10
Nitrogen 3
Calcium 1.5
Phosphorus 1.0
Potassium 0.35
Sulfur 0.25
Sodium 0.15
Magnesium 0.05
Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron 0.70
Lithium, Strontium, Aluminium, Silicon, Lead, Vanadium, Arsenic, Bromine Trace amounts
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Periodic Table of Elements
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Symbols

• Each Element is given a unique Symbol
• First letter of its name (H, C, O)
• First two letters of its name (Si, Ne, Li)
• Taken from its Latin name (Pb, Fe, Au)

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Metals
METAL SYMBOL
Copper Cu
Zinc Zn
Aluminium Al
Iron Fe
Silver Ag
Gold Au
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Non Metals
NON METAL SYMBOL
Carbon C
Oxygen O
Sulphur S
Hydrogen H
Nitrogen N
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Atom

• An Atom is the smallest particle of an Element
  that still retains the properties of that element.

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Whats inside the atom?
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Compounds

• A Compound is a substance that is made up of two
  ore more different elements combined chemically
  together.

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Compounds
O
H
H
Water (H2O)
Methane (CH4)
Carbon Dioxide (CO2)
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Compound ?
O
O
Oxygen (O2)
H
H
Hydrogen (H2)
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• When a compound is formed during a chemical
  reaction its properties differ from those of the
  elements from which it is made

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Mixtures

• A mixture consists of two or more different
  substances mingled together but not chemically
  combined.
• Examples Sea water and salt
• Air nitrogen, oxygen
• Soil sand, clay, humus

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Mixture vs Compound
MIXTURE
COMPOUND
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Mixture Compound
The amounts of the substances in the mixture can vary. The elements in a compound are always present in the same fixed proportion.
A mixture contains two or more substances A compound is a single substance.
The properties of a mixture are similar to those of the substances in a mixture. The properties of a compound are different to those of the elements which reacted to form it.
There are practically no energy changes when a mixture is made Heat is usually given out or taken in when a compound is formed.
It is usually easy to separate the components of a mixture. It is usually difficult to separate the components of a compound.
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