This is the cabon isotope 612C.
The nucleus of carbon-12 has 6 protons and 6 neutrons, while the nucleus of carbon-13 has 6 protons and 7 neutrons. Both isotopes have the same number of protons, which defines them as carbon atoms, but they differ in their neutron count, leading to different atomic masses.
The number 87 when referred to francium is that element's atomic number. The most common isotope of francium is 223, which has a half-life of 22 minutes and decays by beta-negative emission into radium-223.
C14H30 is the formula and 14 carbons are there in kerosene.
It use the symbols as alphabetical characters for element names for examples: C for Carbon, Cu for copper (Cuprum in latin)And in the lower left of the symbol is atomic number, for C it is 6: 6Cin the upper left of the symbol is the mass number, for C it is 12 : 12C(or with another isotope, 13)Then the full nomination: 612C (write 6, and 12 one column aligned)(answer)My chemistry book states that its a Chemical Formula, "a shorthand representation of the composition of a substance using atomic symbols and numerical subscripts"