If you are interested in using monatomics, I would strongly advise that you do a *lot* of reading before you do, particularly the David Hudson materials. There is a great deal more material available in various places. One of the best places for beginners is the Yahoo Group called ORMUS run by Barry Carter.
http://tech.groups.yahoo.com/group/ORMUS/
If you choose to try them, be very careful where you get them. There are a lot of people/groups out there who purport to offer "ORMUS" (Barry's word for these materials) for sale but are in reality selling you what may be toxic materials.
As noted in Mr. Hudson's work, true ORMEs (Mr Hudson's name for these substances - short for "Orbitally Rearranged Monatomic Elements" ) are members of the platinum group of metals and include gold, rhodium, iridium, indium, and a couple of others that I can't remember right off the top. In their dry form, they are pure white, have a flaky appearance and have virtually no weight to them. In fact, they will almost float out of whatever container you keep them in. They are also almost completely tasteless and have a very unique texture when taken orally. They are also *extremely* expensive because of the prices of the metals involved and the difficulty in making them.
If you purchase something that is claimed to be ORMUS but it has color, weight, a salty flavor, and/or grainy texture, then it is very likely *not* true ORMUS and could be a gold or other metal salt, all of which are very toxic.
You *can* get the real stuff, but at the risk of sounding like a conspiracy freak, you will find that no one is willing to tell you how to obtain them, particularly on the Yahoo group I've linked above. This is primarily because apart from Mr. Hudson's research, the effects of these substances are otherwise virtually untested and therefore unknown. Given that, it is not something to be taken lightly without having done a great deal of research on your own, and no one will direct you to where these substances can be purchased because of liability issues should something go wrong.
The research materials are out there, certainly, but few of them have been vetted for accuracy and truthful claims. I have tried true ORME gold and I did have some mild effects from it. They weren't nearly to the extent that is described in the Hudson materials and other testimonies, but I was only able to take it for about a month due to the cost, and the recommended period for the full effect is up to nine months of consistent use.
I know it will sound odd, but if you close your eyes in a silent, dark room and concentrate your attention on the area just below and behind your ears, you will probably hear a tone that is always there. (It's different from tinnitus, which is obvious and recognizable and has a medical cause). This "background tone" is your body's personal frequency (that's not an accurate description, but it's all I can come up with).
While everyone's experience with ORMUS/ORME materials is unique, one of the more common effects is that they do have an effect on this frequency, often raising it to such a degree that you can literally hear the difference if you're familiar with your own frequency. The ORME gold I used *did* change my frequency during the short time I was taking it, such that the continuous tone was occasionally replaced by a higher-pitched "pinging" sound that sounded like a tuning fork being struck. Unfortunately, as I said above, I was unable to continue with it due to the high cost (at the time, $150 for a small vial that lasted 20-30 days), so I can't say anything about any further effects.
If you're interested, be prepared to read a *lot*, and although you should keep an open mind, read with discernment. Hudson's material is a good place to start, and Barry's Yahoo group is great for further information. Be sure to read as much as you can find before you go barging in with questions, though. Most of your questions will probably be answered through your own reading and research before you get there, and even if they aren't, you'll at least be able to ask your remaining questions in a more intelligent way.
Someone wrote above that ORMEs explode violently in the presence of direct sunlight. Hudson documented this effect, but isolated it to only one of the elements (I think it was ORME iridium, but I don't remember for sure). He said in his materials that it didn't explode, per se, just that there was a rather large, blinding flash, and it was gone.
Someone also posted above about colloidal gold and silver. Although they may be useful, colloidals are *not* monatomics. Monatomics are a completely different state of matter.