P1 2 Bonding+Structure

• high boiling points - they are giant ionic lattices made of pos+neg ions held together by strong electrostatic force, requires a lot of energy to break (so ionic substances are brittle) • conduct electricity when molten or in a solution - ionic compounds contain charged particles, particles become free to move when melted/dissolved as particles in a liquid can flow past each other, this solution is an electrolyte

• metal atoms lose electrons to form positive ions • non-metal atoms gain electrons to form negative ions • electron from metal is lost then gained by non-metal ion by electrostatic force from protons in nucleus • pos+neg ions are attracted by electrostatic force to form ionic substance

hydrogen, water, methane * weak intermolecular forces so have low boiling points * cannot conduct electricity as atoms have no electric charge+ there are no free electrons as they are shared * strong covalent bonds between atoms * larger molecules have higher boiling points

diamond, graphite, silicon dioxide/silica * atoms all joined together with covalent bonds * bonds are strong so substances are hard+ have high boiling points * cannot conduct electricity as no free electrons (except graphite)

• giant ionic lattice of positive metal ions attracted to delocalised electrons • strong electrostatic force between electrons+ions - high melting points • layers of ions can slide over one another - metals are malleable • contains delocalised electrons (are free to move+ carry charge) - conduct heat/elec

• mixture of elements where at least one element is a metal • substances are hard+brittle as elements have different sized atoms - this disturbs the layers+ particles cannot easily slide past each other • pure metals are mixed with other elements to make substances harder for other uses

• brass - copper, zinc • stainless steel - iron, carbon, chromium

• particles actually vary in size • particles are not actually spherical • particles are not actually solid as atoms contain empty space • forces between particles are not represented

• ball and stick diagram: shows arrangement of ions, but inaccurate as ions don’t actually have gaps between them • 3D model: shows arrangement more accurately, but less clear as only outer layers seen

• diamond (four bonds) • graphite (three bonds) • graphene (three bonds) • fullerenes: buckminsterfullerene C60, carbon nanotube (three bonds)

• giant covalent structure • allotrope of carbon • each carbon atom is held in place by four strong covalent bonds - there are no free electrons so cannot conduct electricity • strong bonds so has high melting point • substance is hard due to rigid lattice structure+ bonds

• giant covalent structure • allotrope of carbon • strong covalent bonds between atoms arranged in layers - high melting point (but is lower than diamond) • carbon atoms joined by three bonds - delocalised electrons between layers can conduct electricity - used in electrodes • has weaker forces between layers so atoms can slide past each other - substance is soft+ slippery - used as a lubricant

• giant covalent structure • allotrope of carbon • a single layer of graphite • strong covalent bonds between atoms - substance is strong, used to make composite materials stronger • only one atom thick - transparent, used for touchscreen devices • carbon atoms joined by three bonds - delocalised electrons - conducts electricity

buckminsterfullerene* (sphere), carbon nanotube (tube) * giant covalent structures - hexagonal rings of carbon atoms * hollow shapes - allow drug molecules to be carried around body - used in medicines * high tensile strength - used to reinforce materials (eg. tennis rackets) * high electrical conductivity - used in electrical circuits * large surface area - help make catalysts

• large molecules (made from smaller molecules/ monomers) with atoms joined by strong covalent bonds • strong intermolecular forces due to their size so have higher melting points than simple molecular substances • solids at room temp • bond diagram shortened into brackets with a number at bottom right corner