Strontium-90 has a half-life of 29 years. In how many years will a 1 kg sample of strontium-90 decay and reduce to 0.25 kg of strontium-90?

Answer

58 years

116 years

87 years

29 years

In which color coded area would you find an element that behaves both like a metal and a non-metal? Gray Green Blue Purple

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How can chemists state with certainty that no one will discover an element that would appear on the periodic tabl between sulfur and chlorine

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The suffix "-megaly in the term gastromegaly means:

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What moves in or out of a substance during a change of state?