Who propesed that an atom is a sphere with negative electrons

Thomson discovered negatively charged particles by cathode ray tube experiment in the year 1897. The particles were named electrons. J.J Thomson believed electrons to be two thousand times lighter than a proton. He assumed that an atom is composed of a cloud of negative charge in a sphere of positive charges

b

explanation:

mitosis

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.