A control group is the comparison group that helps to "make sure your experiment works." A control group is separated from the rest of the experiment and nothing happens to it kinda like a controlled variable. Controlled variables are the variables in a experiment that remains the same for example a temperature, time, type of products, etc..
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Answer;
-(2) An atom is mostly empty space.
Experiment
-Rutherford conducted the "gold foil" experiment where he shot alpha particles at a thin sheet of gold. The conclusion that can be drawn from these experiment is that an atom is mostly empty space.
-Rutherford found that a small percentage of the particles were deflected, while a majority passed through the sheet. This caused Rutherford to conclude that the mass of an atom was concentrated at its center, as the tiny, dense nucleus was causing the deflections.
Answer:
D. Supported by observations
Explanation:
Because theories change over time, they both need to be proven, they do not go off of consensus, but they do need to be supported by observations.
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The atomic mass number does<span> not change because a </span>beta<span> particle has a much smaller </span>mass<span> than the </span>atom<span>. The </span>atomic number<span> goes up because a neutron has turned into an extra proton. </span>Beta decay<span> is fundamentally different from alpha </span>decay<span>. An alpha particle is made of two protons and two neutrons.</span>