This element has 80 electrons and is considered a transitional element. What am I?

How many joules of heat are absorbed to raise the temperature of 650 grams of water from 5.00c to it's boiling point, 100c

Iknow the answer is a but i don't know why

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?