inorg chem

1) The answer is typical, when moving across a period, the effective nuclear charge of the atom increases and hence it will pull the electrons harder, making a smaller atomic radius.

2) Energetically favourable refers to whether a reaction is exothermic or endothermic.

Kinetically favourable refers to whether a reaction is sponataneous, i.e. if the reactants react immediately when they com across each other, without any external assistance.

Say, the combustion of methane in oxygen is energetically favourable but NOT kinetically favourable since they don't react immediately when mixed but needs an ignition to initiate due to a pretty high activation energy.

However, acid-base neutralization is both energetically and kinetically favourable since as soon as they are mixed, they react immediately.

2011-01-23 22:43:42 補充：
Yes, kinetically stable also refers to "low activation energy"

2011-01-23 22:44:12 補充：
Sor, should be kinetically favourable

2.
kinetically favorable: why don't mention "small activation energy" or "low energy barrier"?