What are the various letters used by Bohr to represent electron shells in an atom?

State whether the following statements are true or false:

(a) Thomson proposed that the nucleus of an atom contains protons and neutrons.

(b) The cathode rays obtained from all the gases consist of negatively charged particles called electrons.

(c) The anode rays obtained from all the gases consist of positively charged particles called protons.

Name the central part of an atom where protons and neutrons are held together.

Name the particles which actually determine the mass of an atom.

Name the positively charged particle present in the atoms of all the elements.