Cesium.
Groups are the vertical columns that run up and down while periods are the horizontal rows. So to find the answer to this, go to the first column (Group 1) and find the sixth period (row 6) which will land you on Cesium, element 55.
Hope this helps!
Au^2S^3+ 3H^2 = 2Au + 3H^2S
Erosion
waethring
deposition
pressure or heat
all of this can change the form of rock to another
The first one would be it
Atomic mass / mass number / atomic weight
(all of which mean the same thing)