Answer:
Name, Thallium. Symbol, Tl. Atomic Number, 81. Atomic Mass, 204.3833 atomic mass units. Number of Protons, 81. Number of Neutrons, 123. Number of Electrons, 81 ... It has a metallic luster when it is first exposed to air but it tarnish quickly
Explanation:
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Einstein's theory of special relativity sets of the speed of light, 186,000 miles per second (300 million meters per second). ... The speed of light in a vacuum is 186,282 miles per second (299,792 kilometers per second), and in theory nothing can travel faster than light.
Exothermic reactions transfer energy to the surrounding, usually as heat.