Step-by-step explanation:
An atom consists if an electron, proton and a neutron. These are called as subatomic particles.
The mass of electron is

The mass of proton is

The mass of the neutron is

The atomic mass of an element is the sum of protons and electrons. An element is defined as the species that has same number of protons.
A chemical compound is defined as the species that are composed of more than one molecules.
So, the correct order is electrons, protons, neutrons, elements and compounds.