1/ that single electron in the outer shell is only weakly held because of sheilding effects from electrons in lower orbitals. it only 'sees' a fraction of the charge of the one excess proton.
2/you can touch Na with the uncovered hand, though if your sweaty then it will get quite warm. unless of course it is reffering to the layer of sodium hydroxide that would appear as a barrier. excluding that, you can even hold Rb in your bare hands as long as they don't sweat(or you wouldn't have any hands) i've done it though only for a few seconds as my hands were getting pretty warm by then.
3/metallic bonds are looser than ionic bonds.