Natural science gr8

• Atom


  Tiny particles that make up all matter
• Subatomic particles


  • Protons (positive charge)
  • Neutrons (no charge)
  • Electrons (negative charge)
• Proton


  • Found in nucleus
  • Positively charged
  • Number of protons identifies the atom
• Neutron


  • Found in nucleus
  • Uncharged
  • Exerts a binding force keeping protons together in the nucleus
• Electron


  • Moving around the nucleus
  • Negatively charged
• Nucleus


  • Central core of the atom
  • Contains all the protons and neutrons
  • Positively charged because of its protons
• Element


  • Composed of identical atoms
  • Simplest form of matter that cannot be broken down into simpler substances
• Periodic table


  Arranges elements in order of increasing atomic number
• Information in periodic table

  • Atomic number
  • Name of element
  • Symbol
  • Atomic mass
• Groups


  • Vertical columns in periodic table
  • Elements in each group have similar chemical properties
• Periods


  • Horizontal rows in periodic table
• Types of elements


  • Metals
  • Semi-metals
  • Non-metals
  • Noble gases
• Molecule


  Chemical combination of two or more atoms
• Chemical bond


  Force that binds two atoms together
• Chemical formula


  Representation of elements and their ratios in a molecule
• Compound


  Combination of two or more elements
• Atoms of same element combine

  Substance is still an element
• Atoms of different elements combine

  Substance formed is a compound
• Compound


  • Salt (sodium chloride, NaCl)
• Decomposition by heating


  Heat breaks down compound into simpler compounds or elements
• Decomposition by heating


  • Potassium permanganate (KMnO4) decomposes into other compounds and oxygen
• Decomposition by electrolysis


  Electricity decomposes compounds into their elements
• Decomposition by electrolysis


  • Water (H2O) decomposes into hydrogen and oxygen
  • Copper chloride (CuCl2) decomposes into copper and chlorine
• Chemical reaction


  Two or more substances react to form a new substance with different properties
• Reactants


  Substances that react with one another
• Products


  Substances that are formed in a chemical reaction
• Synthesis reaction


  Two or more reactants combine to form a single product
• Decomposition reaction


  A single reactant produces multiple products
• Mixture


  Combination of two or more substances that are not chemically bonded
• Mixtures


  • Air
  • Soil
  • Seawater
• The properties of a mixture are different from the properties of its individual components
• Reactants


  Substances that react with one another in a chemical reaction
• During a chemical reaction, chemical bonds of the reactants break and new bonds form to produce the products
• Types of chemical reactions

  • Synthesis reaction
  • Decomposition reaction
• Synthesis reaction


  A type of reaction in which two or more reactants combine to form a single product
• Decomposition reaction


  A type of reaction where a single reactant produces many products
• Mixture


  A loose assortment of different substances that are not chemically joined
• Examples of mixtures


  • Iron filings and sulfur
  • Oxygen and nitrogen
  • Iron filings and sugar
  • Oxygen and carbon dioxide
  • Water and alcohol
  • Sugar and salt
  • Air (oxygen, nitrogen, carbon dioxide)
• The different substances in a mixture can be separated by simple physical methods such as filtration, distillation and magnetic separation
• Mixture


  • Has two or more substances NOT chemically joined
  • Individual components retain their properties and do not possess new properties
  • The constituents can be easily separated by simple physical methods
  • Substances can be mixed in any proportion