Structure Of An Atom Flashcards
What are protons and neutrons collectively called.
Nucleons
Describe where electrons are in an atom.
They orbit the nucleus but in between the nucleus and orbiting electrons there is empty space.
What are the charges of each sub-atomic particle ?
Proton - +1
Electrons - -1
Neutrons - 0
What is the mass of each sub-atomic particle ?
Proton - 1
Electron 1/1840
Neutron- 1
What is the standard nucleus and why ??
A mass unit is defined using Carbon- 12 because it’s mass per nucleon have averages that are close to whole numbers.
What is the mass of an atomic mass unit ?
1/12 the mass of one atom of Carbon-12.
Why is a standard atom necessary.
The mass of protons and neutrons varies depending on the nucleus.
What is mass number.
The sum of the number of protons and neutrons in the nucleus of an atom.
What are isotopes.
Have a different mass number but same atomic number. different versions of the same atom with a different number of neutrons.
What is a neutral atom ?
An atom which has an equal number of protons and neutrons.
Who created the basic model for atomic structure and draw this ??
Rutherford-Bohr
Describe who and what was discovered about the atom.
Sir JJ Thompson detected the electron and measured its mass to charge ratio.
Lord Rutherford detects the proton and measured its mass to charge ratio.
Millikan measure the charge of an electron.
Chadwick detected and measured the properties of the neutron.
What was Geiger and Marsdens experiment ?
Alpha particles (He2+) we’re fired at thin gold foil.
Most were past through unaffected.
Few were deflected.
Very few were reflected back towards the source.
What did Geiger-Marsdens experiment show ??
The mass of the protons and neutrons and the positive charge of the neutrons is concentrated to a very small nucleus.
Most of the atoms volume is empty but there is space containing electrons called energy levels.
