Atomic Structure Test Flashcards
What was Democritus theory of matter
Described matter as being composed of tiny particles that were indivisible
What was aristotiles theory of matter
Did not except the idea of atoms
What was daltons atomic theory
All matter composed of small particles called atoms
Atoms of a given element are identical
Atoms cannot be created, divided, or destroyed
Atoms combine in whole number ratios
Atoms are separated, combined, or rearranged in chemical reactions
What parts of daltons theory were true
All matter is composed of small particles called atoms
Atoms combine in whole number ratios
What does daltons theory of an atom look like
A black sphere
What was thomsons atomic theory?
Discovered electrons
Described atoms as being composed of electrons embedded in a mass of positive charge
Is called plum pudding model (or chocolate chip cookie model)
Looks like chocolate chip cookie
What was rutherfords atomic theory
Discovered the nucleus of an atom
Concluded that positive particles are centrally located in atoms
Rutherfords model is positive in center , electrons surrounding itp
Protons and neutrons (not discovered yet) huge compared to electrons
What was Chadwick’s atomic theory
Discovered neutrons
Chadwick’s atom protons and neutrons surrounded by electrons
What was bohrs atomic theory
Described the organization of electrons in atoms
Identified quantized energy levels as distinct circular paths followed by electrons in atoms
Is called the planetary model
Model looks like protons and neutrons in center, surrounded by electrons in energy levels
What’s the modern atomic theory
Describes electron movement as wavelike and in clouds instead of distinct circular paths
What’s the Heisenberg uncertainty principle
The exact position and exact speed of an electron can never be known so the same time
Heisenburgs model is protons and neutrons in center, waves where you don’t know exactly where electrons are
How do atoms differ
Atomic number
Mass number
What’s atomic number
The number of protons in the nucleus of an atom
Is unique for each element
What’s the mass number
The number of protons and neutrons in an atomic nucleus Not on periodic chart Ex Carbon-12 6pt 6nt Carbon-13 6pt 7nt
What are isotopes
Atoms of a particular element that have different numbers of neutrons in their nuclei (same # of protons)
Neutrons have to do with mass, not charge
