Question

Why is Na+ smaller than K+?

Answer 1

What do you think?

Answer 2

I think i got it.. Isn't it because of the size or the ions increasing going down a period?

Answer 3

you want to think of it in terms on atomic number. what does it represent?

Answer 4

Atomic number increases across a period. Na+ and K+ they both have 1 electron and 1 proton so why is Na+ smaller than K+? I just need an explanation

Answer 5

Have you heard of the concept of electron shielding? Na has far less electrons therefore much less shielding from the charge that the positively nucleus has on the electrons. K has more electrons than Na therefore it has more electrons that could potentially block the attraction of the nucleus on the furthest electron. For Na+ you have now lost an electron so the shielding on the now outermost electron just became even smaller and the ion of Na+ becomes even smaller. This also happens with K+ and the outermost electron also now has less shielding which in turn draws it closer to the nucleus. However K+ still has more electrons and more shielding occurring than Na+ does. Also it is known that atomic size increases moving down a group and this trend is known to be unchanging when involving ions of equivalent charges.

Answer 6

Na+ and K+ dont have 1 electron and 1 proton.

Answer 7

Yes got it! thank you so much yea sorry i didn't mean 1 electron and 1 proton i meant that they are both in the same energy level (1) one loses one electron and one gains an electron. Thank you sweetburger :)

Answer 8

ok sorry for the misunderstanding. Glad to help :)