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Matter and particles - Coggle Diagram

- - - - Mixtures:
        
        impure and consists of two or more substances (elements or compounds) that are NOT chemically combined together.
        
        no reactions
        
        similar properties as its components
        
        melt and boil over a range of temperatures
        
        separated by physical means
  - - - 2. Hardness
        • The strong electrostatic forces of attraction between oppositely-charged ions make ionic compounds resistant to deforming.
        • Hence, ionic compounds tend to be hard, as these forces cause the ions to resist motion.
        • However, when enough force is applied, the ions move away from their lattice positions.
        • When this happens, ions of the same charge approach each other, and the repulsive force between these ions causes the lattice structure to shatter
        Therefore, ionic compounds are hard but brittle
        
        3. Solubility
        • Many ionic compounds are soluble in water, but insoluble in organic (eg. Ethanol, Acetone) solvents.
        • When ionic compounds are dissolved in water, we say that they are in the aqueous state.
        
        4. Electrical conductivity
        • Ionic compounds conduct electricity ONLY when in molten or in aqueous state.
        • In the molten and aqueous states, the strong electrostatic forces of attraction between ions are overcome.
        • The mobile ions carry the electric current when a potential difference is applied
        Note: They can't conduct electricity in solid state because the ions are held in fixed positions by strong electrostatic forces of attraction, hence there are no mobile ions to carry the electric current when a potential difference is applied
  - - - 2. Solubility
        • Most covalent substances are insoluble in water (but there are exceptions such as ammonia, acids, alcohols) but soluble in organic solvents (e.g. ethanol).
        
        3. Electrical conductivity
        • Most simple covalent molecules are unable to conduct electricity.
        • Reason: Covalent substances exist as simple molecular structure. Absence of mobile charge carriers (mobile ions or electrons) to carry a current when a potential difference is applied.
        • However, some covalent molecules can dissociate in water to form a solution that can conduct electricity. For example, hydrogen chloride dissociates in water to form mobile H +and Cl –ions.
  - - - 2. Solubility
        • Most macromolecules are insoluble in water and soluble in organic solvents.
        
        3. Electrical Conductivity
        • Most macromolecules cannot conduct electricity in any states due to the absence of mobile charge carriers (mobile ions or electrons).
  - - - 2. Electrical Conductivity
        • Usually do not conduct electricity (except graphite).
        • Reason: All the valence electrons in the atoms are used to form covalent bonds. The strong covalent bonds hold the atoms in fixed positions. Hence, there are no mobile charge carriers (mobile ions or electrons) to carry a current when a potential difference is applied.
        
        3. Solubility
        
        Insoluble in water and insoluble in organic solvents
        
        4. Hardness
        • Usually hard (except graphite is soft)
        • A large amount of force is required to break the extensive network of strong covalent bonds.
        • Some of these substances are used as abrasives. Diamond is the hardest natural material known to us. In the industries, it can be used for cutting other hard solids.
        
        Note:
        Properties of graphite that are atypical of giant covalent structures
        1. Good conductors of electricity:
        • Each carbon atom is covalently bonded to three other carbon atoms.
        • Each atom has one valence electron that is not used in bonding.
        • These electrons are free and mobile to conduct electricity.
        2. Soft:
        • The layers of carbon atoms are held by weak intermolecular forces of attraction.
        • These layers can slide over each other easily when a force is applied.
  - - - 2. Electrical Conductivity
        • Metals are good conductors of electricity.
        Reason: It has free moving (delocalised) electrons to carry a current when a potential difference is applied.
        Note: Unlike ionic compounds which only conduct electricity in aqueous or molten state, metals conduct electricity both when solid and molten.
        
        3. Ease of Shaping
        • Metals are malleable, which means they can be easily shaped.
        • Metals are also ductile, which means they can be stretched.
        Reason: The layers of atoms in a metal can slide over each other easily when a force is applied. The metal does not break as the ‘sea of delocalised electrons’ holds the ions together through strong metallic bonds.
        Note: For metals, when the positively charged ions slide over one another, the ‘sea of electrons’ are still holding them together, hence, metals are not brittle.
        
        4. Heat Conduction
        • Metals are good conductors of heat.
        Reason: Delocalised electrons can move within the metal lattice. Heat energy is transferred easily by these mobile electrons.
    - - An alloy is a mixture of a metal
        with other elements
        (can be non-metals)
      - Similar to metals, alloys generally have high melting and boiling points, and are good conductors of heat and electricity.
        
        • In an alloy, the atoms of different elements are of different sizes. Since the regular lattice arrangement is disrupted, a larger force is needed to make the layers slide over each other.
        • Alloys tend to be less malleable and less ductile than the pure metals they are made from.
        • Alloys are harder and stronger than pure metals.
- - - - Liquefying gas (gases stored as liquids)
        
        Volume of the liquid substances shrinks significantly
        
        Thus, require less storage (storage tanks/truck deliveries)
  - - - Isotopes are atoms of the same element with the same number of protons but different number of neutrons.
        
        Isotopes have the same chemical properties. This is because the atoms have the same number of valence electrons.
        
        Isotopes have slightly different physical properties. For example: the 3 hydrogen isotopes have slightly different boiling points.
- - - - Positive ions: Cations
        Negative ions: Anion
- - - - Naming simple ionic compound
        
        The metallic element is named first, followed by the non-metal element
        
        The non-metallic element changes its name to end in –ide.
        eg: Magnesium Chloride
  - - - Note: When drawing, non-bonding pairs of electrons need to be placed together
      - Naming simple covalent compound
        
        Covalent compounds containing oxygen: end with oxide.
        
        In general, the element with the smaller Group number is named first, followed by the other element which will end with an –ide.In general, for elements in the same group, the element with the higher period is named first, followed by the other element which will end with an –ide.
        
        In general, for elements in the same group, the element with the higher period is named first, followed by the other element which will end with an –ide.
        
        If the first element has only one atom in the molecule, mono- is sometimes not needed. Examples: CO2 is named carbon dioxide and N2O5 is named dinitrogen pentoxide. no of atoms prefix no of atoms prefix 1: mono-. 2: di- . 3: tri- . 4: tetra-. 5: penta- . 6: hexa-.
  - - - • Metallic bonds are formed due to the delocalisation of the valance electrons of the metal atoms over the entire metallic structure, resulting in a lattice of positive ions surrounded by a ‘sea of delocalised electrons’.
        • These positive ions are closely packed and orderly arranged in layers.
        • Metallic bonding is the electrostatic force of attraction between the positive metal ions and the ‘sea of delocalised electrons’.
        
        Note: When drawing, draw at least 3 x 3 ions