a level chem concept qn

fluppocinonys SG

Hi,

for all elements, the larger their size the less reactive they are?

I don't understand because reactivity depends on an atom's valence electrons, if the atom is large, the attraction between nucleus and valence electrons should be weaker, and isn't it more easier for a large size atom to lose its valence electrons, hence more reactive?

How about molecules? The larger their size, the less reactive they are?

Thanks!

UltimaOnline SG

Hi,

for all elements, the larger their size the less reactive they are?

How about molecules? The larger their size, the less reactive they are?

Thanks!

Yes, that's the reason why the reactivity of Grp I and II metals increase down the group, because their oxidation potentials increase (as you go down the group).

Similarly yet conversely, the reactivity (hence oxidizing strength) of halogens increase up the group, because of the stronger electrostatic attraction of the nucleus for the valence shell (as you go up the group), meaning that their reduction potentials increase (up the group).

And again similarly yet conversely, the reducing strength of the halide ions increase down the group, because of the weaker electrostatic attraction of the nucleus for the valence shell (as you go down the group), meaning that their oxidation potentials increase (down the group).

Thus, F2 is the strongest oxidizing agent, and I- is the strongest reducing agent.