Elements, Compounds, and Mixtures

1
Chapter 3

• Elements, Compounds, and Mixtures

2
Elements What are they?

• Pure substances made of only one kind of atom.
• ATOMS ARE TINY STRUCTURES
• Elements are distinguished by its atomic number
  (number of protons)
• 84 elements are found naturally
• Separated in nuclear reactions only, cant be
  broken down into simpler substances

3
Properties of Elements

• are specific to it and act as the identification
  card for that element
• Physical Properties boiling point, melting
  point, freezing points, density, temperature,
  appearance, color , shape and size, hardness, and
  state of matter
• Chemical Properties reactivity to acid,
  flammability

4
Three Categories of Elements

• Metals (shiny, conductors of thermal and
  electrical energy, malleable, ductile)
• Ex. Iron, Copper, Tin
• Nonmetals (dull, insulators for thermal and
  electrical energy, brittle)
• Ex. Neon, Bromine, Sulfur
• Metalloids ( shiny or dull, semiconductors,
  malleable or brittle)
• Ex. Silicon, Boron

5
Structure Diagram

• Atom single particle
• Ion Charge atom (particle)
• Molecule 1 particle made of 2 or
  more atoms
• Element collection of atoms of the same kind

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Compounds

• Two or more kinds of atoms chemically bonded
• Pure substances
• Separated in a chemical reactions
• Elements are chemically combined and join in a
  very specific ratio
• they form new properties that are different from
  the elements in it

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Structure Diagram

• Compounds

H
H
O-2
H20 Water
8
Element or Compound?
methane, CH4
sulphur, S8
compound
element
(Click for answer)
(Click for answer)
hydrogen peroxide, H2O2
sulphuric acid, H2SO4
compound
compound
(Click for answer)
(Click for answer)
oxygen (ozone), O3
carbon (buckyball), C60
element
element
(Click for answer)
(Click for answer)
9
Mixtures

• Combination of two or more substances physically
  combined
• There is no change in the substance making up the
  mixture elements keep their identity
  (properties)
• No definite ratios for mixtures
• Physically separated by
• Distilling, evaporating, using a magnet, or
  picking it apart, filtering

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Mixture Parts and Types

• Solution mixture that looks like it is all one
  substance
• Can be a gas, liquid, or solids
• Homogeneous mixture appear the same throughout
• If it is a solid solution, it is know as an alloy

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• Solute/Solvent one substance (Solute) dissolve
  in the other (Solvent)
• How much solute dissolves in solvent is know as
  concentration.
• Saturated solution is when the solute has reached
  it max.
• Solubility of a solute is the amount needed to
  make a saturated solution.

12
Structure Diagram
This is a mixture of elements made up of atoms,
elements made up of molecules, and compounds. In
a mixture, the particles are not joined together.
Atom, molecule or compound? (click for answer)
atom
Atom, molecule or compound? (click for answer)
molecule
Atom, molecule or compound? (click for answer)
compound