approx. 31 g.
One sixteenth of a gram. 1st halflife- 1/2 gram 2nd, 1/4 3rd 1/8th 4th halflife, 1/16th
3.9 x 10^9
10 grams... If the half-life is 100 years, that means after 100 years, half the original mass remains. After another 100 years, the mass is halved again. 40/2=20... 20/2=10.
The half-life of a radioactive element is the time required for one-half of the nuclei of a radioisotope sample to decay to products.Half-life (t½) is the time required for a quantity to fall to half its value as measured at the beginning of the time period.
About 5700 years. The half-life of carbon-14 is 5700 years, and the question is asking how long for 200 grams to become 100 grams. That is half, so the answer is 5700 years. It will take another 5700 years for the mass to further decay to 50 grams, and another 5700 years to decay to 25 grams.
After each half-life, half of the radium-226 will decay. Therefore, after four half-lives, 1/2^4 or 1/16th of the original gram of radium-226 will remain unchanged. This means that 1/16th of a gram, or 0.0625 grams, will still be unchanged after four half-lives.
One sixteenth of a gram. 1st halflife- 1/2 gram 2nd, 1/4 3rd 1/8th 4th halflife, 1/16th
100 grams
500 grams of radium is equal to 2,21 moles.
3.9 x 10^9
One Half-Life :-)
100 grams
18 grams are one fourth of the original sample mass of 72 grams. Accordingly, the half life is 6.2/4 = 1.55 days.
5,730 years
5,730 years
The density of radium at about room temperature is 5.5  g·cm−3. That's 5.5 grams per cubic centimeter, or 5.5 grams per milliliter. A link to the Wikipedia article on radium is provided.
Radium is not a common commercial product; radium is sold only to qualified and authorized research laboratories, generally in the form of radium chloride solutions or neutron sources Ra-Be.