Boiling Point: -153.4°C
Melting Point: -157.2°C
Period Number: 4
Names of all the elements in its group: Helium, Neon, Argon, Krypton, Xenon, Radon, and Ununoctium

Bentor, Yinon. "Period Table: Krypton." Chemical Elements. N.p., n.d. Web. 16 Nov 2011. <http://www.chemicalelements.com/elements/kr.html>.