Acontainer holds a pure sample of a radioactive substance with a half-life of 2 hours. which of the following statements are true?

a) after 1 hour, less than 50 % of the original atoms in the container will have decayed.
b) after 1 hour, more than 50 % of the original atoms in the container will have decayed.
c) after 2 hours, 50 % of the original atoms in the container will have decayed.
d) after 4 hours, 25 % of the original atoms will have decayed.
e) after 4 hours, the total number of atoms in the container will be reduced by 75 %.

C, because a half-life is the amount of time it takes for half the atoms to decay.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).