You can also buy lots of metals as 1 cm cubes
https://www.amazon.com/Tungsten-Aluminum-Cube-Set-1cm/dp/B01MYFH3VJ
(1 cm cubes have been used as scale references in photos long before bananas.)
The plexiglass is full of carbon, hydrogen and oxygen, so there’s that.
Yes, as Randall indicated, which means that that bottom row will be in constant flux as the decay products decay themselves in turn until they finally hit a stable isotope, leaving a huge smouldering radioactive crater in the ground.
Don’t forget the five elements in the air in your room! We’re not giving that away for free you know! 
Given your Avatar avatar, those would be earth, fire, water, air, and ???
I thought this thread was going to be about this.
No, no apparently that is a different word from “duped” as in scammed.
That’s a duplicate Kirk.
Oh wait, isn’t a “dupe” as in duplicate or fake, just another way of saying scam or rip-off?
Never mind.
No, they’re unrelated words. “Dupe” meaning to copy comes from “duplicate” which comes from Latin “duplicare” meaning “to double”. “Dupe” meaning to scam or deceive comes from French “dupe” or “duppe” meaning “a deluded person”.
Though you might get duped by a duplicitous person. Basically “two-faced”.
Or a bird. It seems. Hooboo or something like that. Considered a dumb bird. I guess.
“Dupe” like copy or “Dupe” like hooboo bird?
I don’t know.
Think I’m gonna believe it my way. Keep it straight in my head.
Don’t need to confuse a Dodo bird and Hooboo bird when I call someone a “Dupe” or a fake who effing scammed me on a periodic table of fake (or “duped”) elements embedded in acrylic.
If you want to be absolutely positive that you aren’t getting duped, this one seems pretty legit. It is a touch bigger and you want to make sure you mount it on studs, not drywall. It’s also back-ordered, but that just means that it must be a bargain.
[sorry for the ‘just a GIF,’ but it needed to be done]
Here is what happened to a guy in Australia who wanted the same thing:
After ordering various radioactive samples over the internet in an effort to collect the entire periodic table, Emmanuel Lidden pleaded guilty to two charges: moving nuclear material into Australia and possessing nuclear material without a permit.
While his actions were criminal, the judge concluded that Lidden had mental health issues and displayed no malicious intent. He is the first person in Australia to be sentenced under the 1987 nuclear non-proliferation act for the importation and possession of nuclear material without the appropriate permits.
The delivery of the materials – which included a quantity of plutonium, depleted uranium, lutetium, thorium and radium – led to a major hazmat incident in August 2023. The entire street that Lidden lived on was closed off and homes were evacuated as Australian Border Force officials, firefighters, police and paramedics investigated.
That one looks good, but what I really want is a periodic table table or a periodic table ^2, If you get a coffee table periodic table, the squares for the radioactive elements could be used to keep your coffee hot (though ideally not hot, as in radioactive).
And while doing research on periodic table tables, you may want to build a chart showing the various options, including the number of elements included and their cost. That could be a periodic table table table or a periodic table ^3.
Another option; I’m thinking of writing a comprehensive large format tome on the history of the periodic table and all of the elements. A periodic table coffee table book in other words.
How in the heck did that guy get ahold of ‘a quantity’ of plutonium, I wonder?!? I thought that, as one of the most toxic substances in the world, it was also one of the most tightly controlled.
Just get hydrogen and label it ‘some assembly required’
Everything changed when krypton attacked.
“Oh, my God, they found me, I don’t know how, but they found me. Run for it Marty!”
Here you go.