Question

@) Use the figure below to answer which bond types are likely in the compounds • Mgo • HF • GaAs (b) Use chemical reasoning, or take the help of the equation below to arrange the following ionic compounds by grid enthalpy, from high to low. Suppose they all have the same crystal structure, • NaCl • LCI • Mgo . SO (c) Look up the melting points of the compounds in task (b) in SI data and rank from low to high melting point. Does the order of melting points correspond to that expected based on the calculation of grid number piers in task (b)? If not, why? Hjälpmedel Metallic Covalent Anº - Nalang (1-) d' = 34.5pm 34 5m

Answer 1

a) ionic Mgo - Ionile HF - Ionic GaAs - Covallent -Covalent Metallir (1-do from the figure, we see that covalent bonds are likely in the Compound b) AH, = NAIZA ZBI - 4a &od Since, grid enthalpy is inversely proportional to a tie Size of cation and anion Hence, lid > Nach Mgo > sro Also go is smaller than Nael. Hence overall order can be Lice Mo Nace sro • Melting poent: - Nace o lice because Na has higher reactivity 80 it more easily lose ė than Li and make more stronger bond than li → M907 Sro because of smaller size 9 mq, its lattice energy is very high