History of the atom Flashcards
(26 cards)
What is the basic unit of matter?
Atom
Who proposed the first atomic theory in the early 19th century?
John Dalton
True or False: Atoms can be created or destroyed in a chemical reaction.
False
What model of the atom did J.J. Thomson propose?
Plum pudding model
Fill in the blank: The nucleus of an atom contains ______ and ______.
protons, neutrons
Who discovered the electron?
J.J. Thomson
What did Ernest Rutherford’s gold foil experiment demonstrate?
The existence of a dense nucleus
What is the charge of a proton?
Positive
Who developed the planetary model of the atom?
Niels Bohr
True or False: Neutrons have a positive charge.
False
What is the mass of an electron compared to a proton?
Much smaller
Which scientist is known for the uncertainty principle related to electron positions?
Werner Heisenberg
What is the primary component of the atomic nucleus?
Protons and neutrons
Fill in the blank: The atomic number of an element is determined by the number of ______ in its nucleus.
protons
Who first proposed the concept of the atom around 400 BC?
Democritus
What is an isotope?
Atoms of the same element with different numbers of neutrons
True or False: The Bohr model only applies to hydrogen atoms.
True
What is the primary function of electrons in an atom?
To participate in chemical bonding
What did Niels Bohr introduce to explain electron orbits?
Quantized energy levels
Which experiment led to the conclusion that atoms are mostly empty space?
Rutherford’s gold foil experiment
What are the three primary subatomic particles?
Protons, neutrons, electrons
Fill in the blank: The modern atomic theory incorporates quantum mechanics and ______.
wave-particle duality
Who proposed the wave theory of electrons?
Louis de Broglie
What does the term ‘nuclear fusion’ refer to?
The process of combining two atomic nuclei to form a heavier nucleus
