| In the 19th century, the prevailing idea was that atoms were tiny indivisible spheres. | Early Atom Model |
| What was the prevailing view of atoms in the 19th century? | In the 19th century, people thought that atoms were tiny spheres that could not be divided. |
| The discovery of negatively charged particles called electrons by J.J. Thomson in the late 19th century. | Discovery of Electron |
| What discovery challenged the idea of indivisible atoms? | The discovery of the electron showed that atoms were made up of smaller particles. |
| A model of the atom proposed by J.J. Thomson where electrons were embedded within a sphere of positive charge. | Plum Pudding Model |
| What was the plum pudding model of the atom? | The plum pudding model depicted the atom as a ball of positive charge with negatively charged electrons scattered throughout it. |
| A scientific experiment conducted in the early 20th century by Ernest Rutherford to investigate the structure of the atom. | Rutherford's Experiment |
| What experiment did Rutherford conduct to investigate the structure of the atom? | In the early 20th century, Rutherford carried out the alpha particle scattering experiment. |
| Particles consisting of two protons and two neutrons, emitted by some radioactive substances, with a positive charge. | Alpha Particles |
| What are alpha particles made of? | Alpha particles are made of 2 protons and 2 neutrons and have a positive charge. |
| The hypothesis that alpha particles would pass straight through a gold sheet in Rutherford's experiment, based on the assumption that positive charge in atoms is evenly distributed. | Plum Pudding Model Prediction |
| What was the prediction about the behavior of alpha particles in Rutherford's experiment? | The scientists predicted that the alpha particles would pass straight through the sheet without deflection. |
| A model of the atom proposed by J.J. Thomson where electrons were embedded within a sphere of positive charge. | Plum Pudding Model |
| What model of the atom influenced the prediction in Rutherford's experiment? | The prediction was based on the plum pudding model of the atom, where positive charge is very spread out. |
| The outcome of Rutherford's experiment, which did not align with the predicted behavior of alpha particles. | Experimental Results |
| How did the experimental results of Rutherford's experiment compare to the prediction? | However, the results of the experiment did not match their prediction. |
| An experiment conducted by Ernest Rutherford in 1909 to study the structure of the atom by bombarding a thin gold foil with alpha particles. | Rutherford's Alpha Particle Scattering Experiment |
| What was the purpose of Rutherford's alpha particle scattering experiment? | To study the structure of the atom by bombarding a thin gold foil with alpha particles. |
| The observation in Rutherford's experiment where most alpha particles passed straight through the gold foil without any deflection. | Most Alpha Particles Passed Through |
| What was observed in Rutherford's experiment regarding the majority of alpha particles? | Most alpha particles passed straight through the gold foil. |
| The conclusion drawn from Rutherford's experiment that most of the atom is comprised of space through which alpha particles can pass without significant deflection. | Empty Space |
| What did the observation of most alpha particles passing through the gold foil suggest about the atom's structure? | It showed that most of the atom was empty space. |
| The observation in Rutherford's experiment where a small fraction of alpha particles were deflected backward at large angles after striking the gold foil. | Some Alpha Particles Were Deflected Backwards |
| What was observed in Rutherford's experiment regarding some alpha particles? | Some alpha particles were deflected and repelled backwards at large angles. |
| The conclusion drawn from Rutherford's experiment that the mass of the atom was concentrated at its center, known as the nucleus, disproving the plum pudding model. | Concentrated Mass at Nucleus |
| What did the observation of some alpha particles being deflected backwards indicate about the distribution of mass in the atom? | It showed that the mass of the atom was concentrated at its center, known as the nucleus. |
| The conclusion drawn from Rutherford's experiment that the mass, concentrated in the nucleus, was positively charged. | Positive Charge Concentrated in Nucleus |
| What did the concentration of positive charge in the nucleus indicate in Rutherford's experiment? | It indicated that the mass was positively charged. |
| The conclusion drawn from Rutherford's experiment that the plum pudding model of the atom was incorrect. | Disproved Plum Pudding Model |
| What was the outcome regarding the plum pudding model of the atom based on Rutherford's experiment? | Rutherford's experiment disproved the plum pudding model of the atom. |
| A model of the atom proposed by Ernest Rutherford, which replaced the plum pudding model and depicted the atom as consisting of a small, positively charged nucleus surrounded by negatively charged electrons. | Nuclear Model of the Atom |
| What model replaced the plum pudding model of the atom? | The nuclear model of the atom. |
| The concept in the nuclear model of the atom that suggests the majority of the atom's volume consists of empty space. | Empty Space |
| According to the nuclear model of the atom, what characterizes most of the atom? | Most of the atom is depicted as empty space. |
| The idea in the nuclear model of the atom that the majority of the atom's mass is concentrated at its central core, known as the nucleus. | Concentration of Mass at Nucleus |
| What is the distribution of mass like in the nuclear model of the atom? | The atom's mass is concentrated at its centre, in the nucleus. |
| The nucleus of the atom in the nuclear model is positively charged, containing protons. | Positively Charged Nucleus |
| What is the charge of the nucleus in the nuclear model of the atom? | The nucleus is positively charged. |
| Negatively charged electrons that move in orbits around the positively charged nucleus of an atom, as depicted in the nuclear model. | Orbiting Electrons |
| How are electrons arranged in the nuclear model of the atom? | Negative electrons orbit the positive nucleus in the nuclear model of the atom. |
| An improvement upon the nuclear model proposed by Niels Bohr, which suggested that electrons orbit the nucleus at specific distances. | Bohr's Model of the Atom |
| What did Niels Bohr propose in his model of the atom? | Niels Bohr proposed that electrons orbit the nucleus at specific distances. |
| Fixed distances from the nucleus in Bohr's model of the atom, where electrons orbit at specific energy levels. | Electron Shells |
| What are the fixed distances from the nucleus in Bohr's model sometimes called? | They are sometimes called electron "shells". |
| Empirical evidence and observations that corroborated Niels Bohr's theory of electron orbits in the atom. | Experimental Support for Bohr's Model |
| How was Niels Bohr's theory of electron orbits in the atom supported? | Bohr's theory was supported by experiments and observations. |
| The identification of positively charged particles within the nucleus of an atom, each carrying a consistent amount of positive charge. | Discovery of Protons |
| What did scientists discover about the positive charge of the nucleus? | Scientists showed that the positive charge of the nucleus was divided into smaller particles. |
| Positively charged particles found in the nucleus of an atom, each possessing the same amount of positive charge. | Protons |
| What were the smaller particles within the nucleus with a consistent positive charge called? | These particles were called protons. |
| The determination of neutral particles within the nucleus of an atom, distinct from protons and electrons. | Discovery of Neutrons |
| What was discovered in later experiments alongside protons? | Later experiments revealed the presence of neutral particles in the nucleus, known as neutrons. |
