What is the region of the atom where electrons are found

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

In salt water solution,the salt is the blank

How many significant figures are in the following numbers ? a. 0.0002030 b. 2.000 c. 2.008900 d. 145.00