0

Guest

Courses New

why hydration enthalpies of alkali metal ions decrease with increase inionic sizes?

why hydration enthalpies of alkali metal ions decrease with increase inionic sizes?

Grade:

5 Answers

gopal krishna
14 Points
12 years ago

with increase insize of ions the charge dencity decrease and the ion can attract less no of water molecules so the process releases less amoun of energy

Ashwin Muralidharan IIT Madras
290 Points
12 years ago
Hi Nishant,
With the increase in size of the alkali metal, it is difficult for the metal to be surrounded by water molecules. Hence less energy is released when the size increases, and hence the trend.
Hope this helps.
Best Regards,
Ashwin (IIT Madras).
Amarjeet Kumar
11 Points
7 years ago
With increase in size of atoms the nuclear force of attracting water molecules decreases as the distance between the nucleus and water molecules increases and hence it becomes easy to separate the water molecules from an atom
Abhishek Mittal
26 Points
7 years ago
as we know that water is a polar molecule where the oxygen atom has a partial negative charge.  Also as lithium has the smallest ionic size its positive field(due to its high effective nuclear charge it attracts negative charges effectively and also due to the absence of numerous inner elcetron its screening effect is also very low compared to the other alkali metals) is very strong. It atrracts the electronegative aprt of the water molecule effectively than the other ions of alkali metals(i.e. they have a larger size and their ability to attract the electronegative part of the water molecules decreases -large size due to which the nucleus of the ion is far away from the water molecule leading to a reduction in attractive force).
RD
22 Points
6 years ago
Hii nishant
the hydration enthalpies of alkali metal ions decreaseswith increases  ionic size  
Li+>Na+>K+>Rb+>Cs+
Li+ has maximum degree of hydration and for this reason lithium salts are mostly hydrated eg.LiCl.2H2O.
Due to its high effective nuclear charge and less screening effect it is very strong ion 
hope it help
Regards
RD.

Think You Can Provide A Better Answer ?

Other Related Questions on Inorganic Chemistry

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More