bonding and structure (2) Flashcards
one way in which diamond differs from graphene and graphite
poor electrical conductivity
what is the trend in boiling temperatures of hydrogen halides
hydrogen chloride-> hydrogen iodide increases as size of halogen atoms increases (more electrons) which increases the strength of the London forces
hydrogen fluoride has a permanent dipole
what happens when ammonia gas reacts with hydrogen chloride gas
acid base
what is a metallic bond
electrostatic force of attraction between positive metal ions and delocalised sea of electrons
what is an ionic bond
electrostatic force of attraction between oppositely charged ions
what is a covalent bond
electrostatic attraction between two nuclei and the shared pair of electrons
which has higher melting temperatures, group 1 or 2
group 2:
-higher charge so electrostatic forces harder to overcome as electrons more attracted to nucleus
-smaller ionic radius due to added electron increasing attraction to nucleus, harder to overcome forces
which has higher melting temperatures, period 1 or 2
period 1: smaller ionic radius
what do metals and acid make
hydrogen gas and salt
what do metals and water make
metal hydroxide and hydrogen gas
why do ionic compounds have high melting temperatures
because each ion is surrounded by multiple other ions so there are a large number of forces to be overcome, ionic bonds require more energy to break
why do ionic compounds conduct in solution/when molten
when solid there are no free ions so unable to carry charge
when dissolved in solution ions are free to move and carry charge
properties of ionic compounds
-hard solids
-soluble in water
-brittle
what is ionic bond strength affected by
1) higher charge on cation/anion = stronger forces
2) closer packed ions = stronger forces
3) geometry
evidence that ions exist
electrolysis, migration of ions
physical properties: high melting temp + solubility in water required
