# “Editing” atom nucleus

First of all. I am really bad at chemistry and all that. So this might or more likely will sound at least primitive... But this question has been bothering me for far too long.

So, I was reading about an atom. How all different kinds of it differ by the number of protons in its nucleus. And that gave me this utopian thought: maybe in far (like, really far) future we will have some sort of super "printers" which could take anything as their "ink" and somehow turn that anything (a brick for example) into manageable atoms.

Then it probably should identify each atom, by counting its protons and edit it by "deleting", "adding" or separating needed number of the protons and neutrons.

So my question is... Do you think this is theoretically possible? Are there any known ways of changing the number of protons?

• Theoretically possible perhaps, but I would be amazed if such a thing ever became practical. In a very direct sense, you start off by inverting a nuclear weapon; that is, you'd be taking the equivalent of the explosive yield of a nuclear device to pulverize a couple of kilograms of matter into ink. After that's done, then by setting the ink, you're redetonating the nuclear device that was just inverted. Managing that amount of energy for so little product is absurd, not to mention that even an outstanding energy efficiency of 99% would imply a colossal power input to keep it going. – Nicolau Saker Neto Feb 12 '15 at 22:48
• Your talking about sth what is called nanoassemblers, but generally they aren't thought to change atoms they are given as input - if you'd want assembler to make sth from iron, you should give it iron, not for ex. titanium and expect it to turn into iron via nuclear reactions. – Mithoron Feb 18 '15 at 12:45
• Transforming a nucleus isn't really chemistry but nuclear physics. Also to transform a nucleus to a different atomic number takes a lot of energy. To look at it another way, the atomic bomb dropped on Hiroshima converted less than the mass of a US penny into energy. – MaxW Aug 21 '16 at 21:07

In part, your vision already exists and uses electrons as "ink". In a process kown as electron capture, a proton "swallows" an electron of sufficient energy and is thus converted to a neutron.

$$\ce{^{A}_{Z}X + e- -> ^{A}_{Z-1}Y + \nu_{e}}$$

As a consequence, the atomic mass number A remains the same, but the atomic number Z is decreased by one: Element X is converted to element Y.

A typical example would be the conversion of aluminium to magnesium:

$$\ce{^{26}_{13}Al + e- -> ^{26}_{12}Mg + \nu_{e}}$$

Theoretically it's possible to create atoms from raw particles and to assemble them; science fiction posits "replicators" in Star Trek, http://en.wikipedia.org/wiki/Replicator_%28Star_Trek%29, and elsewhere.

It is done, a few billion or trillion atoms at a time, when matter is bombarded by protons in a cyclotron or linac. Americium, 241Am, for example, was first produced that way, and you probably have some in smoke detectors in your house, though now it is extracted from the random products of nuclear fission reactions. See http://en.wikipedia.org/wiki/Americium.