Beginning of Essay
is element number 54 on the periodic table of the elements. It has a mass of roughly 131 atomic mass units. There are 77 neutrons and 54 protons in the nucleus of the atom. The symbol for is Xe and it belongs to the family of elements called the noble gases. ....

Middle of Essay
.... elements that have different boiling points. Basic-ally, when a sample is heated, the faster element leaves first, leaving the second element behind. Krypton was known to have a boiling point at a temperature that is lower than xenon. So the scientists could predict that heating the mixture would leave krypton in the container, while the faster boiling xenon leaving it. After the two scientists separated krypton and xenon, they identified it as a new element through the emission spectrum of the gas. Xenon is used heavily in light bulbs. Many of the bulbs in camera flashes have xenon in them, because they can be used over 10,000 times without ....