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reactivity increases DOWN the group

Extra shells of electrons means there is increased shielding, and therefore atomic radii increases

even though nuclear charge increases, the extra shieldi...

To make life easier we often treat molecules as flat - for example we draw methane on a page as a carbon with 4 hydrogens bonded to it at perfect 90 degree angles. This isn't really the case. Electron-ele...

Br2 molecules are larger than Cl2 molecules, so more electrons are present in Br2 molecules. Therefore there are stronger van der waals forces between Br2 molecules than Cl2 molecules, so more energy is n...

Molar mass of CH₄ = 12 + 4(1) = 16 mass = Mr x moles mass = 16 x 7.23 mass = 115.68g = 116g (3sf)

Diamond is an extremely strong and rigid substance because of its molecular structure, which is giant covalent structure. This means that every carbon is covalently bonded to 4 other carbon molecules to f...