摘要：Revision: Halogens Trends in chemical properties chlorine will displace bromine and iodine bromine will displace iodine but not chlorine iodine will displace neither chlorine or bromine Oxidizing Power F2Cl2Br2I2 Reactions with Cl2 Reactions with Br2 Reactions with I2 Trend in electronegativity decreases as atomic number increases Trend in boiling point all exist as diatomic molecules attraction = weak intermolecular forces van der Waals forces i
Revision: Halogens
Trends in chemical properties
chlorine will displace bromine and iodine
bromine will displace iodine but not chlorine
iodine will displace neither chlorine or bromine
Oxidizing Power
F2>Cl2>Br2>I2
Reactions with Cl2
……
Reactions with Br2
……
Reactions with I2
……
Trend in electronegativity
decreases as atomic number increases
……
Trend in boiling point
all exist as diatomic molecules
attraction = weak intermolecular forces
van der Waals forces
increase with size of molecule
Tests
Tests for halide ions
Reagents
……
Energetics
Standard enthalpy of formation
enthalpy change when 1 mol of a compound is formed from its elements under standard conditions
all reactants and products in their standard states
Standard enthalpy of combustion
enthalpy when 1 mol of a substance is completely burned in oxygen
under standard conditions and all reactants and products in their standard states
Standard enthalpy of neutralization
enthalpy change that accompanies the neutralization of an acid by a base to form 1 mol of H2O
under standard conditions
Standard conditions
298 K
100kPa
1mol dm-3
Redox
Oxidation
loss of electrons
addition of oxygen
Reduction
gain of electrons
loss of oxygen
Reactions which involve both oxidation and reduction
Oxidizing agent is reduced – an electron pair acceptor
Reducing agent is oxidized – an electron pair donor
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