chemistry mock revision

Old period table (3 points)

arranged by increasing atomic weight

blank spaces were left for undiscovered elements

limitations as isotopes were unknown

new periodic table (4 points)

arranged by increasing atomic number

includes structure, e.g. groups and periods

metals and non metals are divided

isotopes are shown

why is chlorine gas at room temp?

chlorine is a gas at room temperature because is it simple molecular. This means it has weak intermolecular forces of attraction, which don’t require lots of energy to overcome

why is sodium chloride a solid at room temperature?

sodium chloride is a solid at room temperature because it is a giant ionic lattice. This means that there are strong electro static forces of attraction between between oppositely charged ions which requires lots of energy to break