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Chemistry - Coggle Diagram

- - - - three types of strong chemical bonds: ionic, covalent and metallic
      - for ionic bonding the particles are oppositely charged ions
      - Ionic bonding occurs in compounds formed from metals combined with non-metals
      - for covalent bonding the particles are atoms which share pairs of electrons
      - Covalent bonding occurs in most non-metallic elements and in compounds of non-metals
      - for metallic bonding the particles are atoms which share delocalised electrons
      - Metallic bonding occurs in metallic elements and alloys
    - - The particles in an ionic bond are oppositely charged ions
      - Outer shell electrons are transferred to complete a whole outer shell so that there is 8 outer shell electrons.
      - Metal + NON-Metal
      - Metal atoms lose electrons - they become positive ions ( as there are more protons than electrons) - OXIDATION
      - Non-metal atoms gain electrons - they become negative ions ( there are more electrons than protons - REDUCTION
    - - Giant structures of ions
      - Held together by strong electrostatic forces of attraction between the oppositely charged ions
      - Forces of attraction act in all directions in the lattice ( this is ionic bonding)
      - Example of ionic compound is NaCl.
        
        KEY
        
        Red = Na+, Green = Cl-
      - DOT AND CROSS DIAGRAM for ionic bonding
    - - MAY consist of small molecules
      - Some covalently bonded substances have very large molecules,such as polymers.
      - Some covalently bonded substances have giant covalent structures, such as diamond and silicon dioxide.
      - Dot and cross covalent bonds
    - - Metallic bond particles are atoms that share DELOCALISED electrons.
        
        Delocalised electrons are outer shell electrons that are free to move
      - Giant structures that have a REGULAR arrangement of the atoms
  - - - Solid
        
        Rigid, fixed shape and fixed volume ( not compressible)
      - Liquid
        
        Not rigid and no fixed shape, FIXED VOLUME ( not compressible)
      - Gas
        
        Not fixed shape, not fixed volume and is not rigid ( can be compressed)
      - Solid to Liquid
        
        Melting
      - Liquid to solid
        
        Freezing
      - Gas to liquid
        
        Condensation
      - Liquid to gas
        
        Evapouration
      - Gas to solid
        
        Deposition
      - Solid to gas
        
        Sublimation
    - - Gas
        
        (g)
      - Liquid
        
        (l)
      - Aqueous ( a substance that is dissolved in water)
        
        (Aq)
      - Solid
        
        (s)
    - - They have high melting and high boiling points due to there being a large amount of energy required to break the strong bonds between atoms
      - They have regular structures (giant ionic lattices)
        
        There are strong electrostatic forces between the atoms/particles in the lattice in all directions
      - Can conduct electricity when in melted/ molten or aqueous form
        
        The ions are free to move so charge can flow
  - - - Graphene is a single layer of graphite and has properties that makes it useful in electronics and composites
      - Fullerenes are molecules of carbon atoms with hollow shapes
      - structure of fullerenes is based on hexagonal rings of carbon atoms
        but they may also contain rings with five or seven carbon atoms
      - first fullerene to be discovered was Buckminsterfullerene (C60)
        which has a spherical shape
      - Carbon nanotubes are cylindrical fullerenes with very high length to diameter ratios. Their properties make them useful for nanotechnology, electronics and materials
    - - each carbon atom forms four covalent bonds with other carbon atoms
      - in a giant covalent structure, so diamond is very hard
      - has a very high melting point and does not conduct electricity
    - - each carbon atom forms three covalent bonds with three other carbon atoms
      - forming layers of hexagonal rings that have no covalent bonds between the layers
      - one electron from each carbon atom is delocalised
  - - - Advantages
        
        :diamond_shape_with_a_dot_inside:Displayed formulae are 2D representations and are basically simpler versions of the ball and stick model
        :diamond_shape_with_a_dot_inside:Adequately indicate what atoms are in a molecule and how they are connected
        
        Disadvantages
        
        :diamond_shape_with_a_dot_inside:Fail to illustrate the relative sizes of the atoms and bonds
        :diamond_shape_with_a_dot_inside:Cannot give you an idea of the shape of a molecule and what it looks like in 3D space
    - - Advantages
        
        :diamond_shape_with_a_dot_inside:Useful for illustrating the arrangement of atoms in 3D space
        :diamond_shape_with_a_dot_inside:Especially useful for visualizing the shape of a molecule
        
        Disadvantages
        
        :diamond_shape_with_a_dot_inside:Fails at indicating the movement of electrons
        :diamond_shape_with_a_dot_inside:The atoms are placed far apart from each other, which in reality is not the case as the gaps between atoms are much smaller
    - - Advantages
        
        :diamond_shape_with_a_dot_inside: Useful for illustrating the transfer of electrons
        :diamond_shape_with_a_dot_inside: Indicates from which atom the bonding electrons come from
        
        Disadvantages
        
        :diamond_shape_with_a_dot_inside:Fails to illustrate the 3D arrangements of the atoms and electron shells
        :diamond_shape_with_a_dot_inside:Doesn’t indicate the relative sizes of the atoms
  - - - Atoms and small molecules 0.1nm
      - Nanoparticles 1 to 100 nm
      - Fine particles (also called particulate matter - PM 2.5) 100 to 2,500 nm
      - Coarse particles (PM10, or dust) 2500 to 10,000 nm
      - Thickness of paper 100,000 nm
    - - medical treatments
      - cosmetics, deodorants and sunscreens
      - electronics
      - catalysts
    - - small size of nanoparticles makes it possible to breathe them in
      - Once inside the body, they might catalyse reactions that are harmful
      - Toxic substances could bind to them because of their large surface area to volume ratios, harming health if the nanoparticles do get into the body.
      - Modern nanoparticulate materials have only become common recently, so it is difficult for scientists to determine their risks
- - - - elements that react to form positive ions are metals
      - elements that don't react to form positive ions are non-metals
      - majority of elements are metals (found to the left and bottom of periodic table)
      - non-metals are found towards right and top of periodic table
    - - called noble gases, unreactive and don't easily form molecules as have full stable outer shell
      - going down the group, boiling points increase, and relative atomic mass increases
    - - before discoveries scientists classified elements in order of atomic weight
      - early periodic tables, incomplete and mixed up in wrong places
      - Mendeleev left gaps for new discoveries and changed some elements if didn't match properties of group
      - isotopes explain why atomic weight order was not always correct
    - - known as alkali metals, have single electron in outer shell
      - reactivity of elements increase when going down the group
    - - arranged in order of atomic (proton) number
      - elements with similar properties are in groups (columns)
      - elements in the same group have the same number of outer shell electrons, giving them similar chemical properties
    - - called halogens, have similar reactions and 7 electrons in outer shell
      - non-metals, consist of molecules made of atoms
      - examples: chlorine, bromine, iodine
      - further down in the group has higher boiling point, melting point and higher relative molecular mass
      - reactivity of elements decreases as goes down the group
      - more reactive halogen can displace less reactive halogen from aqueous solution of its salt
- - - - Moles are the measurement of chemical amount. and the symbol unit for moles is Mol
      - The mass of one mole of a substance is equal to the relative formula mass
      - For example, the mass of one mole of H20 = 18 = 1+1+16 and the mass of one mole of Mg = 24
      - Avogadro's Constant
        
        6.02 x 10^23
        
        The number of atoms, particles,molecules or ions in a mole of a given substance is a constant.
      - Number of moles = mass (g) :heavy_division_sign: Ar OR mass (g) :heavy_division_sign: Mr
    - - Chemical equations can be interpreted in terms of the moles
        
        For example : Mg+ 2HCI :arrow_right: MgCI2+H2
        
        And this produces one mole of Magnesium chloride and one mole of Hydrogen gas
        
        There are 2 moles of hydrocloric acid to every mole of Magnesium
      - Masses of products and reactants can be calculated
    - - The balancing numbers (normal script numbers) in a symbol equation can be calculated from the masses of the reactants and products.
        
        Convert masses in grams to amounts in moles then convert moles into simple ratios to find moles of wanted product/reactant;
    - - The reactant that is completely used up during a chemical reaction
        
        Limiting reactants limit the amount of product produced
        
        Therefore less moles of products are made
    - - Concentration is the measurement of mass per a given volume of solution.
        
        g/dm^3
        
        grams per decimetre cubed
        
        Mol/dm^3
        
        Moles per decimetre cubed
      - Concentration = mass :heavy_division_sign: volume
        
        Higher volume/ volume is raised = lower concentration
        
        Higher mass/ mass is raised = higher concentration
      - Concentration conversions
        
        From to mol/dm^3 to g/dm^3
        
        :heavy_multiplication_x: by the relative formula mass.
        
        From to g/dm^3 to mol/dm^3
        
        :heavy_division_sign: by the relative formula mass