-2
$\begingroup$

As per noble gas configuration $\ce{Na+}$ should be more stable than $\ce{Na}$. But at the same time $\ce{Na+}$ has a positive charge so it will be easily attracted by negative charge while $\ce{Na}$ will remain unaffected in presence of negative charge. So accordingly, should not $\ce{Na}$ more stable than $\ce{Na+}$? Please help me get out of this confusion.

$\endgroup$
  • 2
    $\begingroup$ If you mix NaCl with elemental sodium, nothing will happen. So they have the same stability??? $\endgroup$ – Karsten Theis Dec 19 '19 at 4:05
  • $\begingroup$ Actually, if you put $\ce{NaCl}$ and metallic $\ce{Na}$ to two separate beakers full of water, which would catch fire? $\endgroup$ – Mathew Mahindaratne Dec 19 '19 at 4:57
  • 3
    $\begingroup$ You can't compare stability of these two things. It simply makes no sense. $\endgroup$ – Ivan Neretin Dec 19 '19 at 5:23
  • 1
    $\begingroup$ In vacuum Na is certainly more stable than its ion and a free electron. This is crystal clear. But see also Ivan Neretin comment (you cannot compare different things, at least one should be aware of the differences) as well as the answer by Poutnik. $\endgroup$ – Alchimista Dec 19 '19 at 8:36
  • 1
    $\begingroup$ context is all. Under what conditions is the question asking about (if it doesn't specify them, it is a bad question). $\endgroup$ – matt_black Dec 19 '19 at 13:45
2
$\begingroup$

Relative stability of both depends on environment.

In gaseous atomic phase $\ce{Na}$ is somewhat more stable than $\ce{Na+}$ and $\ce{e-}$ pair due the needed ionization energy.

In water, Na is very unstable, as a big amount of energy is released by reaction of $\ce{e-}$ with water and by hydration of Na+. That leads to very fast up to explosive reaction.

Note that this explosion ( that can be accompanied by the hydrogen-oxygen explosion ) is primarily a physical Coulombic explosion due excessive positive charge of melted sodium.

| improve this answer | |
$\endgroup$
  • $\begingroup$ To Poutnik: what causes melted sodium to get an excessive positive charge? Would an explosion occur in the absence of atmospheric oxygen? $\endgroup$ – James Gaidis Dec 19 '19 at 15:02
  • 1
    $\begingroup$ Fast electrons leave sodium much faster than slow sodium ions, what charges sodium positively. Just before Coulombic explosion, sodium builds charged spikes of metallic sodium, pinching through isolation layer of water vapour and hydrogen and by sparks ignites the stuff at contact with air.. It was both simulated by quantum calculations and observed by high speed cameras. Search for recent Nature article. $\endgroup$ – Poutnik Dec 19 '19 at 16:40
  • $\begingroup$ Thanks! I remember now an article about NaK alloy, which is much more reactive. $\endgroup$ – James Gaidis Dec 20 '19 at 14:25
  • $\begingroup$ @James Gaidis. Yes it is. But the main point in using it was it form an eutecticum with low melting point, so they could work with liquid Na-K alloy. $\endgroup$ – Poutnik Dec 20 '19 at 14:28
  • $\begingroup$ Many years ago, I did an experiment with what I considered a small piece of sodium (about 20 grams). I dropped it into a laundry tub (in our basement) which contained about 2 inches of COLD water (because I had read that sodium would explode in hot water). I watched it fizz and zip around on the surface for about 15 seconds; then it suddenly melted and became globular. About 5 seconds later, it blew up, throwing little droplets of sodium all over, but they rapidly burned up. I suppose the spikes could cause sparks. Lithium reacts slower and does not seem to cause explosions. $\endgroup$ – James Gaidis Dec 21 '19 at 14:54

Not the answer you're looking for? Browse other questions tagged or ask your own question.