Krypton: atomic number 36


I am confused by the usage "Kr-33" in the main article on Krypton:

In 1960 it was internationally agreed that the fundamental unit of length, the metre, should be defined as 1 m = 1,650,763.73 wavelengths (in vacuo) of the orange-red line of Kr-33.

What does the 33 refer to?

error in units

The units of resistivity don't come out right.

10^-8 Ohm * m
m Ohm * cm

the 'm' should be a 'mu', but unfortunately they both look the same in the latin alphabet.


Can someone help me find some info on Krypton?

I need the Valence Number
Relative Electro Negativity
Specific Heat
Atomic Radius
And the physical appearence at room temperature...

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