Chemical Forums

Chemistry Forums for Students => High School Chemistry Forum => Topic started by: alexanda on August 11, 2014, 05:21:06 AM

Title: why H has a smaller atomic radius than He
Post by: alexanda on August 11, 2014, 05:21:06 AM

For period 2,3 and4, atomic radius decreases from metals to non metals and it is because the nuclear charge rises gradually

But why He has a larger atomic radius than H instead of smaller?shielding effect between H and He has no change

Title: Re: why H has a smaller atomic radius than He
Post by: Ben Bob2 on August 11, 2014, 11:30:53 AM

There are conflicting views of which radius is greater, due to the difficulty of measuring helium's radius (as it does not form many stable compounds).

http://www.physicsforums.com/showthread.php?t=719342 (http://www.physicsforums.com/showthread.php?t=719342)

Title: Re: why H has a smaller atomic radius than He
Post by: alexanda on August 11, 2014, 10:19:07 PM

Okay thx a lot!