The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

This discussion is now closed.

Check out other Related discussions

effect of heat on carbonates

Can someone explain to me why it is easier for Magnesium carbonate to decompose into MgO and CO2 than Barium carbanate into BaO and CO2.

I think it has sometime to do with the fact that Ba2+ is a larger cation than Mg2+ and therefore it is more stable?

Is this correct?

Thanks in advance.
(I'm doing Nuffield AS btw)
- The magnesium ion is smaller than that of barium
- The small ion has a higher charge density and greater polarising power
- The high polarising power attracts the anions and weakens the bond making the compund thermally unstable, thus little energy is required to decompose it - break it down compared the barium.
thanks!
Reply 3
Avatar for finnstar
finnstar
13
gordon, well answered!
*clap clap*

=)
Reply 4
Avatar for Saffie
Saffie
11
gordon2002
- The magnesium ion is smaller than that of barium
- The small ion has a higher charge density and greater polarising power
- The high polarising power attracts the anions and weakens the bond making the compund thermally unstable, thus little energy is required to decompose it - break it down compared the barium.

ok so is this right?

Thermal Stability increases down the group.
Because as you go down, the ions get bigger due to more shells..
The bigger the ion, the lower charge density and therefore less polarising power.
-It is the polarising power that attracts anions and this attraction weakens the bonds within, making the compound thermally unstable
And the thermally unstable ions break down more easily when heated.

Related discussions

Latest

Trending

Trending

Articles for you