19. cerium is the most abundant rare earth metal. pure cerium ignites when
scratched by even a soft object. it has four known isotopes: "ce (atomic mass
= 135.907 amu), ce (atomic mass = 137.905 amu), 4°сe (atomic mass =
139.905 amu), and "ce (atomic mass = 141.909 amu). ce-140 and ce-142 are
fairly abundant. which is the more abundant isotope?

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Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy

The correct answer is c. orbital shape. "the angular momentum quantum number l describes the shape of an orbital. it corresponds to each orbital type, i.e. (0,1,2,−1)=(s,p,d,f,g,"

The correct answer is "hydrogen".