Activity Series: Understand Why Au is Less Reactive than Pb

[MichaelXY]

[SOLVED] Activity series

In my textbook, it list the acitivty series on a small table but the book does not explain why the series is the way it is. I am a bit confused. From the periodic chart Au looks more reactive than Pb. From what I understand the reactivity goes from left to right on the periodic table. Also Pb seems closer to the non metal side, yet Pb is the more reactive substance based on the activity series. Could someone help shed some light here.

Thanks

 

[eli64]

I can offer a partial explanation...

The activity series is based on many experimental results of these metals (and H) with water, steam and acid. The most active ones start with Li, K ...Ag, Au round out the least active ones.

The most active elements are also the most easily oxidized (wants to lose electrons) and so strongest reducing agents. Vice versa for the least active elements. http://en.wikipedia.org/wiki/Reactivity_series

As far as I know, this is an experimentally observed series that correlates to the standard electrode potentials for these elements to form ions,http://en.wikipedia.org/wiki/Table_of_standard_electrode_potentials

I have also not come across an explanation based on elemental properties like ionization energies or electronegativities


Reactivity increases DOWN group for metals, that is Li < Na < K < Cs < K but the trend ACROSS the periodic table is not true.

 

[MichaelXY]

Thank you very much. Great explanation.

 

[Gokul43201]

Another thing to beware of, while looking at periodic behavior across periods is the desire to look at s-, p- and d-block alaments all together. Many a pitfall lies in that approach. There are cases where you can compare across blocks without fear of being eaten up, but in other cases great caution is advised.

 

[MichaelXY]

I am discovering that some portions of chemistry just need to be memorized. Thanks for the advice.

Just curious, why was this post moved from chemistry? It seemed relevant to chemistry. I only ask so I no better next time.

 

[Gokul43201]

Standard textbook/homework questions belong in the appropriate subforum of the Homework & Coursework forums. It appears a Mentor thought this was a better place for your question.

Read the posting guidelines ("Rules" tab at the top of the page).