Atomic Number definition: The number of protons within the nucleus of x atom.
Atomic Mass definition: The number of protons and/+ neutrons within the nucleus of x atom.
The given information states that the element has 8 protons and 8 neutrons in its nuclei with 8 electrons revolving around it. If the atomic number is 'the number of protons' and we have 8 given protons, our answer would be 8. If the atomic mass is protons + neutrons and we have 8 protons and neutrons, our answer for atomic mass would inevitably be 16.
Therefore
Atomic number: 8
Atomic mass: 16
Hydrocarbon hydrogen thats all ik sorry
Use the formula E=mc^2
energy given=<span>8.1 x 10^16 joules
</span>speed of <span>light = 3.00 × 10^8 m/s
</span>
plug in the values we'll get mass=<span>9.0 x 10-1 kg</span>
Noble gases' outer shells are already filled with 8 electrons (other than He, which has 2, but is still filled and stable). Atoms bond with other elements to fill their outer shell, but they don't need to do that and are already stable.