Yes, you would float on metallic mercury based just on density. Mercury has a density (g/cm3) of 13.5, while the human body (65-80% water) has a density of roughly 1.0. The lower density object would float, or at the very least not sink (remain buoyant), on top of the greater density substance. However, it is important to note that mercury is toxic and should be handled properly. Additionally, if you were to swallow some mercury, it could cause serious health problems.
As mentioned, the metal has a density of about 10 g/cm3. This means that you would need about 11 kg (24 lb) of mercury to make your body completely buoyant. Since 8 oz are equal to 30 ml, this amounts to almost half of what is considered a safe work environment exposure level for mercury. Thus, assuming you were working with a relatively small amount of the substance and using proper safety measures, you could easily float away from dangerous levels of exposure.
However, even with these assumptions, mercury is still highly toxic and should be treated as such. If you were to swallow any amount of it, seek medical help immediately. As well, don't eat anything while you're exposed to it; stop what you're doing and leave the area until further notice.
Because the surface of liquid mercury has very low friction, standing and even walking would be difficult. You could try to jump or run, but it wouldn't do much good because the impact with the ground would not be enough to stop you from continuing to drift downward.
The only way to stop this process is by adding more mercury so that you do not exceed the maximum safe limit for elemental mercury exposure. The amount of mercury that you can be exposed to without adverse effects is about 0.05 mg/m3 over an hour long period. One study found that if one stood in liquid mercury for four hours per day for five days per week for two weeks, there would be no apparent ill effects. However, other studies have shown that even small amounts of mercury are toxic to humans. For example, babies born to mothers who were exposed to high levels of mercury during pregnancy had lower IQ scores than children born to mothers who were not exposed to mercury.
It is not advisable to play in liquid mercury because it can leak out of its container and enter the environment. Also, people should not eat any part of a plant that has grown in soil contaminated with mercury because some of it will also enter their system through their mouth and gut.
Mercury is a metal with a density of 13.5 grams per cubic centimeter (0.49 pounds per cubic inch). This indicates that the density of mercury is around 13 times larger than the density of water. As a result, several items that sink in water will float on mercury, such as lead, silver, and steel. However, the opposite is not true - something that floats in water may not necessarily sink in mercury.
Lead was used for making ammunition, batteries, and other military equipment until it was banned in the 1970s. Lead has a density greater than that of mercury (11.3 g/cm3 vs. 10.8 g/cm3), so it would float on top of the liquid mercury.
Silver has a density less than that of mercury (108 g/cm3 vs. 109.5 g/cm3). As a result, it would sink to the bottom of the container holding it under normal conditions. However, because silver is dense enough to sink in mercury, a small amount of it could be suspended above the surface of the liquid.
Steel has a density greater than that of mercury (7800 g/cm3 vs. 7800 g/cm3). Under normal conditions, it would sink to the bottom of the container it is placed in. However, because lead is less dense than steel, a little bit of lead might only partially sink below the surface of the liquid.