What is the ratio of the rms speed of hydrogen and Helium gases in a container at same temperature?

Explain to someone who knows nothing about fossils the study of invertebrate paleontology and how it scientists understand the history of the earth. be sure your explanation contains a minimum of two complete sentences.

If an atom contains 11 protons in its nucleus, predict the element with the atomic number and electronic configuration. will the number of electrons remain the same during the chemical reaction in such an atom? explain.

What are similarities and differences between refraction, reflection, diffraction and absorption?