You are Here: Home

enthalpy change of hydration Watch

1. I don't understand why the enthalpy change of hydration is more exothermic the smaller the ion. When they're in an ionic lattice I understand why the bonds are stronger (because they can pack closer together), but I don't understand it for this. Something else that is confusing me is- in my book it says 'small ions exert more attraction on water molecules and more energy is released'. How can the size of an ion cause it to attract other molecules more strongly? It just doesn't make sense to me
2. Smaller ions have a higher charge density, which means that it will attract other molecules more strongly.
3. (Original post by Holby_fanatic)
Smaller ions have a higher charge density, which means that it will attract other molecules more strongly.
I googled charge density and it said 'in electromagnetism, charge density is a measure of the electric charge per unit volume of space, in one, two or three dimensions. More specifically: the linear, surface or volume charge density is the amount of electric charge per unit length, surface area or volume'. But I don't seem to understand this concept, so just because a charge is in a smaller volume it's stronger? I don't get how this works.

4. (Original post by tammie123)
I googled charge density and it said 'in electromagnetism, charge density is a measure of the electric charge per unit volume of space, in one, two or three dimensions. More specifically: the linear, surface or volume charge density is the amount of electric charge per unit length, surface area or volume'. But I don't seem to understand this concept, so just because a charge is in a smaller volume it's stronger? I don't get how this works.

The smaller the ion, the closer the electrons are to the positively charged nucleus and that gives it a higher charge density.
Smaller ions give more exothermic values because they can get closer to one another.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 16, 2013
Today on TSR

Am I pregnant?

...or just paranoid?

A robot wrote Harry Potter?

Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.