How much energy does it take to heat 20 g of water from 25 to 55 degrees celsius

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Schrodinger and heisenberg developed an alternate theory about atomic nature that contradicted some of bohr's model of the atom. how do changes resulting from new technology and evidence affect the reputation of the atomic theory?

How many atoms are there in 5.70 mol of mg