Atomic Theory Flashcards
(18 cards)
What are the three subatomic particles in an atom?
Protons, neutrons, and electrons.
What are the charges of protons, neutrons, and electrons?
Proton = +1, Neutron = 0, Electron = -1
Where are protons, neutrons, and electrons found in an atom?
Protons and neutrons = nucleus; electrons = shells (energy levels)
What is the overall charge of an atom?
Neutral – because protons and electrons balance out.
What does the atomic number tell you?
The number of protons in an atom.
What does the mass number tell you?
The total number of protons and neutrons.
How do you calculate the number of neutrons?
Mass number - atomic number
Who was the first person to suggest atoms exist?
John Dalton
What was Dalton’s model of the atom?
A solid sphere that cannot be divided.
What did J.J. Thomson discover?
The electron.
What was Thomson’s model called?
The plum pudding model.
What did Rutherford’s gold foil experiment show?
Atoms have a small, dense, positive nucleus.
What model did Rutherford propose?
The nuclear model.
What did Bohr add to the nuclear model?
Electrons orbit the nucleus in fixed energy levels (shells).
Who discovered the neutron?
James Chadwick
Why was the plum pudding model replaced?
It couldn’t explain results of the gold foil experiment.
Why is the nucleus positively charged?
Because it contains protons (positive) and neutrons (neutral).
Why do electrons stay around the nucleus?
They’re attracted to the positive charge of the protons.
