Atom size particles are evenly distributed and suspended in water molecules, because the silver atoms are so small they do not need chemicals to help them .

http://www.wikihow.com/Select-Safe-Chemical-Free-Colloidal-S...
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Atom Size Particles are trillions of times smaller than a single microgram, this ...
http://stores.purecolloidal.com/4000-ppm-colloidal-silver-16...
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Why you should consider atom size particles: The Rice University has concluded that Low PPM Colloids that contain nano-particles do not work, in fact because .

http://www.colloidal-silver-atoms.com/
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Note added at 2 hrs (2015-02-14 22:21:56 GMT)
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These are silver-atom CLUSTERS . If we take 10 nm (100 Angstroms) as the diameter of the cluster and the lattice constant of bulk silver (4 Angstroms), then we have 25 atoms along the diameter (actually more, as silver has the face-center cubic lattice with four atoms per unit cell) . The number of atoms in such a cluster would be 4*pi*r^3/3 = 8000 atoms. This is what the author must have meant when discussing the atomic dimension of the particles (clusters).

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Note added at 17 hrs (2015-02-15 13:11:12 GMT)
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Cluster, nanoparticle, atoms

Researchers created silver nanoparticles that are chemically stable owing to a robust core of 32 silver atoms (red and green) that together behave as a single atom of a noble gas.

Bigioni’s nanoparticles each contain 44 atoms of silver, arranged in a highly symmetrical pattern.

Each particle is less than 3 nanometres wide, a scale where the silver has very different optical and chemical properties to the bulk metal.
http://www.nature.com/news/easy-route-to-stable-silver-nanop...
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Note added at 17 hrs (2015-02-15 13:24:27 GMT)
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On sizes of silver particles by grinding

The absorbance spectra exhibited amaximum wavelength ( λ max) at 407 – 415 nm for EG stabilizer and 417 – 420 nm for PVAstabilizer. According to Mie theory [24-25], λ max of absorbance spectra can relate to particle diameter. Thus, our results indicated that the obtained silver nanoparticles using EGand PVA as a stabilizer had diameter of 120 and 140 nm, respectively. Silver nanoparticles with light yellow color have been reported a particles size of 120 nm [26].
http://www.academia.edu/8667832/Effect_of_Stabilizer_on_Prep...