Atomic Structure Flashcards
(57 cards)
What charge does a proton have?
+1
What is the relative mass of a proton?
1
What charge does a neutron have?
0
What is the relative mass of a neutron?
1
What charge does an electron have?
-1
What is the relative mass of an electron?
0 (or ~0.0005)
What is the radius of an atom?
1 × 10⁻¹⁰ metres
How much smaller is the nucleus compared to the whole atom?
10,000 times smaller
Where is most of an atom’s mass concentrated?
The nucleus
What happens when an electron absorbs EM radiation?
It moves to a higher orbit
What happens when an electron emits EM radiation?
It falls to a lower orbit
What happens when an electron gains enough energy?
It leaves the atom, forming a positive ion
What are isotopes?
Atoms of the same element with different numbers of neutrons
What does the top number (A) represent in nuclide notation?
Mass number (protons + neutrons)
What does the bottom number (Z) represent?
Atomic number (number of protons)
What does a negative ion mean in terms of electrons?
It has gained electrons
What does a positive ion mean in terms of electrons?
It has lost electrons
What did Dalton believe about atoms (1800s)?
Atoms are indivisible spheres
What did JJ Thomson discover?
The electron
What model did JJ Thomson propose?
Plum pudding model
What did the Gold Foil experiment show?
Atoms are mostly empty space with a dense positive nucleus
Who conducted the Gold Foil experiment?
Rutherford (Geiger and Marsden carried it out)
What model did Bohr propose?
Electrons orbit in fixed energy levels
Who discovered the neutron?
James Chadwick
