The model of the atom has dramatically changed over many many years.We learned atoms make up different substances and are the smallest particles of matter, which have subatomic particles that are very small portions of matter. At first scientist only thought there were electrons which are negatively charged.
Radiometric dating is done on rocks to determine their age
In this technique carbon -14 dating is used to determine the amount of carbon 14 which based on half life of the isotope gives the age of the rock.
Yes it is a exothermic reaction.
1 L=.001 m^3=1.0E^-9 cm^3