HELP!! Derivation of the chemical formula of a compound

1. The organic compound contains 84.21% carbon and 15.79% hydrogen. The vapor density of the compound in air is 3.93. Formulate the molecular formula of the compound.

C8H18

2. The hydrocarbon contains 83.72% carbon and 16.28% hydrogen. Formulate its molecular formula if the vapor mass of 1 liter (n. s) of this compound is known to be 3.84.

C5H10

3. The compound contains 85.71% carbon and 14.29% hydrogen. The vapor density of the compound according to chlorine is 0.986. Formulate its molecular formula.

C5H10​

C5H10

Explanation:

The hydrocarbon contains five carbon atoms and ten hydrogen atoms

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.