How did Mendeleev know that there must be undiscovered elements and how did he take this into account when he designed his periodic table?

Start an single atom tab. observe the decay of polonium-211. after each decay, press the reset nucleus button to watch the process again. write a description of alpha decay for po-211

The nuclear fission process releases neutrons and question 27 options: alpha particles electrons energy beta particles

The ozone molecule o3 has a permanent dipole moment of 1.8×10−30 cm. although the molecule is very slightly bent-which is why it has a dipole moment-it can be modeled as a uniform rod of length 2.5×10−10 m with the dipole moment perpendicular to the axis of the rod. suppose an ozone molecule is in a 8000 n/c uniform electric field. in equilibrium, the dipole moment is aligned with the electric field. but if the molecule is rotated by a small angle and released, it will oscillate back and forth in simple harmonic motion.what is the frequency f of oscillation?