Mercury will be consumed by the Sun. Helium will then fuse to create carbon. The Sun will become a red giant and the Earth's oceans will boil. So much gas will be released from the oceans and surface of the Earth that a run away greenhouse effect will take over our atmosphere. All life on Earth is extinguished.
Carbon fuses to oxygen.
The Sun's outer hydrogen burning shell expands outward. Venus' orbit decays and spirals into the Sun. The Sun becomes a planetary nebula and blows its outer shells into space. When the Hydrogen and helium envelops are cast out into space the Sun becomes a super dense dying star or white dwarf. A cubic foot of white dwarf matter equals 5760 tons.