Structure of the atom and isotopes Flashcards
three scientists which have heavily contributed to our understanding of the structure of the atom are
Ernest Rutherford, J.J. Thomson and James Chadwick.
J.J. Thomson discovered the
electron in 1897
Rutherford discovered the
proton in 1917
Chadwick discovered the
neutron in 1932
the symbol for a proton is
p
the symbol for a neutron is
n
the symbol for an electron is
e-
the relative mass of a proton is
1
the relative mass of a neutron is
1
the relative mass of an electron is
1/1840
the relative charge of a proton is
+1
the relative charge of an electron is
-1
the relative charge of a neutron is
0
protons are found in the
nucleus
electrons are be found in
energy levels surrounding the nucleus
neutrons are found in the
nucleus
Rutherford also discovered that
the atom has a very small core containing the bulk of the mass of the atom.
the energy levels surrounding the nucleus in which electrons exist are called
quantum shells
an element’s mass number is
the number of protons and neutrons added together
the atomic number of an element is
the number of protons which is the same as the number of electrons
an isotope is
an atom of the same element with a different mass, meaning the atomic mass is the same
what did Francis Aston invent in 1919?
the mass spectrometer
what does a mass spectrometer do?
show that not all atoms of an element have the same mass due to differing numbers of neutrons in the nuclei
Aston used his mass spectrometer to discover
the isotope
