History of atom Flashcards
(27 cards)
Who proposed the first atomic theory in the early 19th century?
John Dalton
True or False: The concept of the atom dates back to ancient Greece.
True
Fill in the blank: The term ‘atom’ is derived from the Greek word meaning ‘________’.
indivisible
What did J.J. Thomson discover in 1897?
The electron
Which model of the atom is described as a ‘plum pudding’?
Thomson’s model
Who is known for the planetary model of the atom?
Ernest Rutherford
What experiment did Rutherford conduct to propose the nuclear model of the atom?
The gold foil experiment
True or False: Niels Bohr introduced the concept of quantized energy levels.
True
What is the primary limitation of Rutherford’s model?
It could not explain the stability of the atom.
In which year did Niels Bohr publish his model of the hydrogen atom?
1913
Fill in the blank: The modern quantum mechanical model of the atom was developed in the early ________ century.
20th
Who formulated the uncertainty principle?
Werner Heisenberg
What does the Pauli exclusion principle state?
No two electrons in an atom can have the same set of quantum numbers.
True or False: Electrons are found in fixed orbits around the nucleus.
False
What are the three main subatomic particles?
Protons, neutrons, and electrons
Which subatomic particle has a positive charge?
Proton
What is the mass number of an atom?
The total number of protons and neutrons in the nucleus.
Fill in the blank: An isotope is an atom with the same number of protons but a different number of ________.
neutrons
Who discovered the neutron?
James Chadwick
What is the charge of a neutron?
Neutral
Which scientist is known for the development of the wave mechanical model of the atom?
Erwin Schrödinger
True or False: The electron cloud model describes the probable locations of electrons.
True
What does the term ‘quantum’ refer to in atomic theory?
The smallest discrete quantity of energy.
Which principle explains why electrons occupy lower energy levels first?
Aufbau principle
