8. In the Three Mile Island accident radioactive Krypton-85 was released. Krypton-85 has a half life of 10.8 years. If 1,591 grams of Kr-85 was released, and all of the Krypton-85 fell
to the ground near the reactor, how many years would it take for it to decay to less
than 1 gram? Be sure to show your work. Complete the table provided below to help you
answer the question.
Years
0
10.8 21.6
Half
lives
0
1
2
3
4.
grams 1591
4

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

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