3.1 Flashcards
Metallic bonding involves…
A lattice of positive ions surrounded by a cloud of delocalised electrons
Which two factors contribute to metallic bonding strength?
Number of electrons donated by ions
Size of ions (larger = lower e- density and weaker electrostatic forces)
[Answer structure] Why does Mg have a higher boiling point than Na?
Donation numbers
Size difference
Denser e- cloud
Stronger electrostatic forces require more energy to overcome
Group 2 reactions [3]
2M (s) + O2 (g) –> 2MO (s)
M + 2H2O –> M(OH)2 + H2
MO (s) + H2O (l) –> M(OH)2 (aq)
What pH range do group 2 metal hydroxides have?
10 to 12
True or false: Solubility of group 2 metal hydroxides increases down the group, decreasing pH
False: Solubility of group 2 metal hydroxides increases down the group, INCREASING pH
Ca(OH)2
‘Lime’ to reduce soil acidity
Mg(OH)2
Neutralises stomach acid to treat indigestion
CaCO3
Building material
Chlorine, bromine, and iodine colours
Green, red/brown, grey
Chlorine, bromine, and iodine states at RTP
Gas, liquid, solid
Chlorine, bromine, and iodine colours in water
Pale green, orange, brown
Chlorine, bromine, and iodine colours in cyclohexane
Pale green, orange, violet
Chlorine reaction to produce HCl
Cl2 (g) + H2O(l) –> HCl (aq) + HClO (aq)
Chlorine reaction to produce bleach
Cl2 (g) + 2NaOH (aq) –> NaCl (aq) + NaClO (aq) + H2O (l)
Bleach formula
NaClO
Halide solubilities in ammonia
Chloride - soluble in dilute and conc
Bromide - soluble in conc
Iodide - insoluble
Ammonium test
Heat gently with NaOH
Fumes will turn damp red litmus paper blue
Explain difference in boiling point of NH3 and NH4NO3
NH3 is simple covalent so only needs intermolecular forces to be overcome
NH4NO3 is ionic
Ionic bonds are stronger than intermolecular forces and require more energy to overcome
