"What is the lightest ELEMENT on Earth
with no stable isotope?"
The Big Bang Theory Season 1, Episode 13
stable super-heavy ELEMENT.
The Big Bang Theory Season 7, Episode 10
but they find
the ELEMENT anyway.
The Big Bang Theory Season 7, Episode 10
this stupid ELEMENT
was complain.
The Big Bang Theory Season 7, Episode 10
Now, Element
Lad's ability
The Big Bang Theory Season 7, Episode 3