How many atoms will there most likely be at the third half-life of potassium-40 in this model

At the 3rd half life there are 13 atoms remaining.

Explanation:

Initially we start with a model of potassium-40 atoms which has 50 atoms of it.

We have to find how many atoms would remain at the third half life.

A half life is the time duration with which the number of atoms reduce to half of it's initial number.

At the first half life 50 would reduce to it's half and only 25 would remain .

At the end of the second half life or the starting of the third half life there would be 12.5 atoms remaining. As we cannot express number of atoms as a decimal we round it off to 13.

The number of atoms = 13

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).

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8