The electron configuration for a neutral atom of oxygen would be the final option:
O : 1s^2 2s^2 2p^4.
Knowing that this is a neutral atom of oxygen, and that it posses the same number of electrons and protons, the total number of electrons would be 8. Which can be found out by adding the exponents for each subshell.
B. Density
Density = mass/volume because it’s basically the concentration of mass. How much matter takes up the space. If you pack more matter into less space, it is more dense.
Answer: While conduction is the transfer of heat energy by direct contact, convection is the movement of heat by actual motion of matter; radiation is the transfer of energy with the help of electromagnetic waves. The matter is present around us, in three states, solid, liquid and gas.
I can’t see a picture or question here, sorry