Rutherford reasoned that, since most of the alpha particles went straight through the foil, most of the gold foil was empty space. But what was causing the alpha particles to bounce to the sides and backwards? He realized that some of the alpha particles were hitting a dense (small and heavy), positive center. He called this center the ‘nucleus’. Question: Which atomic model can we eliminate based on Rutherford’s experiment? Claim: Evidence: Reasoning: What’s in the nucleus? Ernest Rutherford (1918) and James Chadwick(1932): Experiments by Rutherford in 1918 detected heavy positive particles that were emitted from atoms. He called these positive particles and reasoned that they must be in the positive nucleus. ‘protons’, However, the atomic model was still not complete. Experiments by Chadwick in 1932 detected a yet another new particle. Colliding atoms together at high speed, he detected uncharged (neutral) particles which he called When Chadwick measured the mass of a neutron, he found that ‘neutrons’. it was heavy, so the neutrons must be located inside the small, heavy (dense) nucleus of the atom with the protons. Where are the electrons? Niels Bohr (1913) With the of the nucleus emerging, one big question remained unanswered. Where were the electrons? Scientists struggled with the question as they couldn’t imagine a stable configuration between the positively charged nucleus and the negatively charged electrons. If protons and electrons held
Rutherford reasoned that, since most of the alpha particles went straight through the foil, most of the gold foil was empty space. But what was causing the alpha particles to bounce to the sides and backwards? He realized that some of the alpha particles were hitting a dense (small and heavy), positive center. He called this center the ‘nucleus’. Question: Which atomic model can we eliminate based on Rutherford’s experiment? Claim: Evidence: Reasoning: What’s in the nucleus? Ernest Rutherford (1918) and James Chadwick(1932): Experiments by Rutherford in 1918 detected heavy positive particles that were emitted from atoms. He called these positive particles ‘protons’, and reasoned that they must be in the positive nucleus. However, the atomic model was still not complete. Experiments by Chadwick in 1932 detected a yet another new particle. Colliding atoms together at high speed, he detected uncharged (neutral) particles which he called ‘neutrons’. When Chadwick measured the mass of a neutron, he found that it was heavy, so the neutrons must be located inside the small, heavy (dense) nucleus of the atom with the protons. Where are the electrons? Niels Bohr (1913) With the of the nucleus emerging, one big question remained unanswered. Where were the electrons? Scientists struggled with the question as they couldn’t imagine a stable configuration between the positively charged nucleus and the negatively charged electrons. If protons and electrons held
09.13.16_ws7_atomic_models_reading.docx