Answer 1) It is incorrect.
Explanation : For the statement;
Thomson did experiments with cathode ray tubes to show that all atoms contain tiny negatively charged subatomic particles called as electrons<span>.
So the statement should be like this:
AFTER the </span><span>Thomson’s experiments, scientists accepted that the atom was made up of smaller particles.
Answer 2) This is correct.
Explanation : Rutherford was the scientist who discovered that atoms has volume is because of the empty spaces inside it. He did the gold foil experiments to prove this and he was successful in doing this by concluding that tiny dense empty places are occupied by positively charged nucleus.
Answer 3) This is Correct.
Explanation : After Thomson and Rutherford, Millikan also performed an experiment to prove that an atom contains a small positively charged nucleus which is usually surrounded by negatively charged electrons by his oil drop experiment.</span>
The atomic number is the total number of protons in the nucleus. The mass number is the total number of particles in the nucleus. That includes the neutrons and the protons. So, the atomic number is 31. When you look at the element on the periodic table with a designated atomic number of 31, that would be Gallium, with a symbol of Ga. Mass number is 31 + 36 = 67. So, the answer is A.
4 protons , 3 protons , 2 protons
HNO2 is the formula for Nitrous Acid