How do physicists create new chemical elements?

I’ve read about physicists being able to create new exotic elements, mainly the ones we all saw at the end of the elements chart in high school. Chemical element - Wikipedia
How do they create those? Is it possible to create stable elements? Is it possible to create elements which already exist or turn some elements into different ones?
I understand that this is getting close to alchemy.

Isn’t there a hypothetical element way down past anything we’ve sythesized in accelerators which is stable (no half-life)? Or is there something in the laws of physics where anything heavier than lead (IIRC) is fated to be radioactive?

In the very simplest terms, an element is defined by the number of protons in its nucleus. If you can add more protons or subtract them, you get a different element. Cyclotrons - or “atom-smashers” - send particles, say a helium nucleus of two protons and two neutrons, or atoms with higher numbers of protons, into target atoms at high energies, “smashing” them together, hence the name. Done properly the nuclei will fuse and a new element will form. No known elements higher than uranium are stable. They decay, often by emitting a helium nucleus or changing a proton into a neutron, each change creating an element with a smaller number of protons. This continues under a stable isotope is formed.

You can start pretty much anywhere and wind up pretty much anywhere if you have the proper combinations and the proper energies. That’s how all elements about lithium are made by stars in the first place. Splitting the atom, like a uranium atom, creates smaller atoms with fewer protons.

The length of time for the decay - measured in half-lives, or the average time it take for half the atoms in a sample to decay - may be in tiny fractions of a second or in billions of years.

There are theoretical islands of stability beyond uranium, but I don’t think any of them are actually stable. They just will last longer than tiny fractions of a second. We aren’t close to any of them yet.

Plutonium was created by bombarding uranium with neutrons.

In general you create new elements by bombarding atoms of existing elements with neutrons, protons or alpha particles. Scientists have been turning atoms of one element into atoms of other elements since the late 1930s or so. Generally the new heavy elements created are very unstable, but there is some chance of finding heavy stable elements that don’t exist in nature (google “Island of Stability” and “Nuclear Transmutation” for more)

Deuterons aren’t neutrons, feller.

Why do you say these things, when you know I will kill you for it?

But could you create some non-exotic elements? E.g.: turn iron into lead or lead into iron.

Sure, or even the fabled lead into gold (though gold into lead turns out to be easier). It’s just insanely expensive, far more expensive than just digging the metals out of the ground.

Is Technetium stable?

No.

Nothing factual to contribute, but for an interesting science fiction examination of the potential hazards of this kind of thing, check out the short story The Bramble Bush by Randall Garrett.