Atomic Theory Flashcards
How has the atomic theory evolved?
the Rutherford model was replaced by the Bohr model when scientists discovered that electrons move in specific orbits around the nucleus.
What is the Billiard Ball Model, made by Dalton?
The Billiard Ball model of the atom was proposed by John Dalton in the early 1800s. He thought atoms were small, hard spheres with no internal parts. Dalton knew that atoms could combine and recombine with each other in whole number ratios to form compounds.
What is the discovery od Electrons and the Raisin Bun Model, made by J.J Thomson?
J.J. Thomson’s experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson’s plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged “soup.”
What is the miniature Solar System Model orbiting electrons, made by Nagaoka?
a model of the atom that contained a small nucleus surrounded by a ring of electrons.
What is the discovery of positively charged nucleus, made by Rutherford?
Rutherford deduced that the atomic nucleus was positively charged because the alpha particles that he fired at the metal foils were positively charged, and like charges repel. Alpha particles consist of two protons and two neutrons, so they are positively charged.
What is the orbiting electrons around positively charged nucleus model, made by Bohr?
Niels Bohr introduced the atomic Hydrogen model in 1913. He described it as a positively charged nucleus, comprised of protons and neutrons, surrounded by a negatively charged electron cloud. In the model, electrons orbit the nucleus in atomic shells.
What is the discovery that the nucleus contained both protons and neutrons, made by Chadwick?
James Chadwick’s contribution to the atomic model was his discovery of the neutron. The neutron is a neutrally charged subatomic particle that is about the same mass as the proton. Both protons and neutrons occupy the nucleus of the atom. Chadwick was able to discover the neutron and measure its mass.
What is Quantum Mechanics where electrons exist in a charged cloud around the nucleus?
An electron cloud represents the area around an atom’s nucleus where electrons are most likely to be found. It is a sphere that surrounds the microscopic nucleus, although it is often rendered as a ring in two-dimensional pictures.
