As the molecules go faster, they are more likely to bump straight out of the liquid and fly off to become a gas. The more molecules that bump out, the higher the vapor pressure. Now, if those molecules have big intermolecular forces like hydrogen bonding or london dispersion forces - when they bump into each other they're more likely to stick.
Often, spoon nails are a sign of iron deficiency anemia or a liver condition known as hemochromatosis, in which your body absorbs too much iron from the food you eat. Spoon nails can also be associated with heart disease and hypothyroidism.
Electrolytes or something along that line that opens up your cell membrane allows better assimilating of vitamins and minerals. However, even though my moons are coming back, my fingernalis are still very brittle. Bottom line, I do think how your fingernails look is a good indicator of things going awry in your body. Sbilek