Grp II - melting points

[BlackPenguin]

hi

Do any of you know why the the first four elements melting points in this grp. seem to not follow any pattern. You would expect them to increase going down the group like they do in all other grps.

The melting points are:-

*Mg: 922K
*Ca: 1112K
*Sr: 1042K
*Ba: 998K

Thanks

[opuntia]

Actually in Group two, the melting temperature falls down the group because as the group descends, the atoms get larger and the bondings become weaker, but Mg does not follow the trend.

[BlackPenguin]

thanks, for clearing that up.

anyone no why Mg doesn't follow the trend

[opuntia]

I enjoyed doing it!

I don't know the reason, but if you like i can ask my teacher that question when the semester begins, that's on 15th of this month. :wink:

[BlackPenguin]

if you can do that it would be great. my teacher wasn't sure of the reason. thanks again

[opuntia]

No problem, i'll ask and tell you what my teacher says

[opuntia]

Originally Posted by BlackPenguin

thanks, for clearing that up.

anyone no why Mg doesn't follow the trend

After a long time i got the answer, or so i guess, it has got something to with the Mg's net nuclear charge...well that's what my teacher told me :roll:

[charco]

your teacher is bluffing

[Paul Robbins]

Originally Posted by BlackPenguin

hi

Do any of you know why the the first four elements melting points in this grp. seem to not follow any pattern. You would expect them to increase going down the group like they do in all other grps.

The melting points are:-

*Mg: 922K
*Ca: 1112K
*Sr: 1042K
*Ba: 998K

Thanks

Best to include the first member of the group to see any pattern.

Be: 1551K
Mg: 922K
Ca: 1112K
Sr: 1042K
Ba: 998K

The pattern is that melting points fall as you look down the group - except for Magnesium. Why does Mg behave oddly? I've no doubt there's a good explanation and if anyone knows it I'd be happy to hear it.

[crun]

Originally Posted by Paul Robbins

Why does Mg behave oddly? I've no doubt there's a good explanation and if anyone knows it I'd be happy to hear it.

Me too.