Use the following electron configuration of europium 1s^ 2 2s^ 2 2p^ 6 3s^ 2 3p^ 6 4s^ 2 3d^ 10 4p^ 6 5s^ 2 4d^ 10 5p^ 6 6s^ 2 4f^ 7 How many principal energy levels are completely filled?

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).

2b2t

explanation:

2b2t