Which two elements on the periodic table share the same period and are both gases? A. Hydrogen and Helium

B. Fluorine and Bromine

C. Lithium and Potassium

D. Xenon and Argon

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.