Khan Academy Atomic History

During a history class, Charlotte, Anika, and Arjun were discussing ancient Greek philosophy. They were trying to remember the Greek philosophers who first proposed the idea of atoms. Can you help them?

• Leucippus and Democritus

• Antoine Lavoisier and James Dalton

• Eugen Goldstein and J.J. Thompson

• Niels Bohr and Werner Heisenberg

Anika, Ethan, and Oliver were discussing the beliefs of Leucippus and Democritus about atoms during their science project. What did they conclude?

• Atoms, like the tiny particles in the sand they were using, make up larger atoms

• Atoms, like the indivisible and uncuttable grains of sand, cannot be divided further

• Atoms, like the different substances in their project, have different properties

• Atoms, like the random distribution of sand grains in their project, are randomly distributed in a positive matrix

During a science fair, Emma, Anika, and Luna were discussing the discovery of electrons. They had different opinions. According to you, who discovered the existence of electrons?

• Leucippus and Democritus

• Antoine Lavoisier and James Dalton

• Eugen Goldstein and J.J. Thompson

• Niels Bohr and Werner Heisenberg

During a science fair, Henry, Daniel, and Arjun were discussing J.J. Thompson's discoveries. Henry asked, 'What did J.J. Thompson call the negatively charged particles he discovered?'

• Corpuscles

• Protons

• Neutrons

• Electrons

In a science project, Liam, Aria, and Anika were asked to research the model of the atom proposed by J.J. Thompson. What was the name of this model?

• Plum Pudding Model

• Planetary Model

• Quantum Theory

• Nuclear Model

David, Abigail, and Henry are discussing a famous experiment in their physics class. Which scientist conducted the gold foil experiment that they are talking about?

• Leucippus and Democritus

• Antoine Lavoisier and James Dalton

• Eugen Goldstein and J.J. Thompson

• Ernest Rutherford

During a science fair, Rohan presented a model of an atom. Emma asked him about the significance of the gold foil experiment conducted by Ernest Rutherford. What did Rohan explain to Emma about Rutherford's discovery from the gold foil experiment?

• Atoms are made up of tiny particles

• Atoms have a neutral charge

• Atoms have a nucleus

• Atoms have randomly distributed electrons

Hannah, Harper, and Emma are studying for their physics exam. They come across Werner Heisenberg's theory about electrons. What did he propose?

• Electrons are like tiny particles

• Electrons are like waves in the ocean

• Electrons have properties of both particles, like a grain of sand, and waves, like ripples in a pond

• Electrons have properties of neither particles nor waves

Michael, Jackson, and Arjun were discussing about the atomic structure in their physics class. They were particularly interested in how Werner Heisenberg described the arrangement of electrons around a nucleus. How did Heisenberg describe it?

• As if the electrons were in circular orbits around the nucleus

• As if the electrons were in specific energy levels and orbitals

• As if the electrons were in random positions around the nucleus

• As if the electrons were in regions of high probability around the nucleus

Sophia, William, and Zoe are discussing the modern model of an atom in their science class. They are trying to figure out what this model is based on. Can you help them?

• Leucippus and Democritus' ideas

• J.J. Thompson's Plum Pudding Model

• Ernest Rutherford's gold foil experiment

• Werner Heisenberg's Quantum Theory