|
The most reactive and electronegative element is ____.
|
argon (Ar)
|
|
Incandescent light bulbs contain ____ filaments.
|
carbon (C)
|
|
Lighter-than-air party balloons are filled with ____.
|
fluorine (F)
|
|
An isotope with a half-life of 24,000 years is ____-239.
|
helium (He)
|
|
An inert gas used in incandescent light bulbs is ____.
|
iodine (I)
|
|
Atoms of H, Li, ____, and K each have one valence electron.
|
plutonium (Pu)
|
|
All ____ atoms have six protons.
|
sodium (Na)
|
|
A black, solid halogen that gives off a purple vapor is ____.
|
tungsten (W)
|
