[oceanscape]

Hi

Can anyone help me with this? I have a question which I do not really understand..

why is the first ionization energy of potassium only a little bit smaller than the first ionization energy of sodium?

Thanks if you can *delete me*

[Eric]

Only thing I can think of is the electron configurations of Na and K are very similar, and since both are Group 1A elements they have very similar properties.  They both have their outermost shell (valence) filled with just one electron, making them both willing to give up that electron to satisfy the electron octet rule.   Does that make sense?

[xiankai]

its easier for K to lose its electron since it has more shells, so the outermost electron experiences less attractive force from the nucleus and more repulsion from more electrons.