It's the ATOMIC number for technetium.
The Big Bang Theory Season 6, Episode 8
I mean, he works with lasers
and ATOMIC magnets.
The Big Bang Theory Season 7, Episode 24
on ATOMIC spectroscopy
when I came across your ad.
The Big Bang Theory Season 9, Episode 8
"Penny, just as Oppenheimer came to regret
his contributions to the first ATOMIC bomb...
The Big Bang Theory Season 1, Episode 2
Helium has
an ATOMIC number of two.
The Big Bang Theory Season 7, Episode 3