Chem test 3

• ELEMENT: Substance made up of Atoms that all contain the same number of Protons (one type of Atom) and cannot be split into anything simpler
• COMPOUND: Substance made up of two or more Elements chemically combined together
• MIXTURECombination of two or more substances (Elements and / or Compounds) that are not chemically joined together
• ION: Electrically charged atom or a group of atoms that are formed by the Loss or Gain of Electronss

  • Loss or gain of Electrons result in the formation of an ion with full outer shell of Electrons
  • Electronic configuration of an ion will be the same as that of a Noble Gas
• IONISATION OF METALS AND NON - METALS

  • METALS: Loses Electrons to another atom and become Positively Charged Ions
  • NON - METALS: Gain Electrons from another atom and become Negatively Charged Ions
• Nitrate: NO3–
• Carbonate: CO32-
• Hydroxide: OH-
• Sulphate: SO42-
• Ammonium: NH4+
• Covalent bonds: strong electrostatic forces of attraction between negatively charged electrons (the bonding pair) and the positively charged nuclei of the atoms involved.
• compounds within ionic bonding always have giant ionic structures
• in ionic compounds the ions are held together in a closely packed 3D lattice structure arrangement by the attraction between oppositely charged ions.
• in ionic compounds the electrostatic attraction between oppositely charged ions is very strong. because a lot of energy is needed to overcome the strong attraction. ionic compounds have high melting and boiling points.
• ionic compound are not electrical conductors when they are a solid . but if you melt ore dissolve them in water they are able to conduct electricity
• covalent molecules that contain only a few atoms are called simple covalent structures.
• most substances that contain simple covalent molecules have low melting and Boiling points and are liquids or gases at room temperature.
• diamond: it is very hard, transparent, has a high melting and boiling points and is chemically unreactive. and each carbon atom forms 4 strong covalent bond with other carbon atoms. many bonds to break means a lot of energy is needed to melt it
• Graphite: A form of carbon in which the carbon atoms form layers. the properties for graphite are the weak forces between layers allow them to slide over each other, the free (delocalized) electrons allow graphite to conduct electricity. the properties are each carbon atom is bonded to only 3 others, forming hexagonal rings
• magnetic metals are : iron, cobalt, steel, nickel (i can see nick)
• Metallic bonding: the electrostatic attraction between positive met ions and delocalized electrons.
• metal atoms usually have a large mass and they pack together into a very small volume.
• Metallic bonds between positive metal ions and delocalized electrons are strong, they have high melting and boiling points, the delocalized electrons moving around allow them to conduct electricity
• SOLVENT:Substance that dissolves a soluteE.g, In salt and water solution, water is the solvent

  SOLUTE:Substance that dissolves in a solventE.g, In salt and water solution, salt is the solute

  SOLUTION:Mixture formed by a solvent and solute

  SATURATED SOLUTION:Solution where no more solute can dissolve (any more solute that is added will settle at the bottom)