31) the mass of an electron is approximately 1/1836
times the mass of
a) 1/1h
b) 2/1h
c) 3/1h
d) 4/2he

 is the correct choice that is option A.

Explanation:

An electron has times the mass of a proton, but an equal and opposite negative charge.

Lets is any element represented here.

Where is the number of protons as well as its atomic number.

And

is the mass number which is the number of protons and neutrons in any atom.

Note: We know that Hydrogen is devoid of neutron,so number of neutrons in a Hydrogen atom is zero.

Then

is also a representation of single proton.

So is the right choice that is option A.

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).