The half-life for the radioactive decay of calcium-47 is 4.5 days. how many half-lives have elapsed after 27 days?

The number of half lives are 6

Explanation:

We are given:

Half life of a radioactive isotope = 4.5 days

Calculating the number of half lives after time has elapsed 27 days:

4.5 days have been elapsed time after 1 half life

So, 27 days must have been elapsed after = half lives

Hence, the number of half lives are 6

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).