Atomic structure and Isotopes Flashcards
What is contained in the nucleus of an atom
protons and neutrons
Where are electrons in an atom
orbit the nucleus in shells
What is the relative charge and relative mass of a proton
rc= +1
rm= 1
What is the relative charge and relative mass of a neutron
rc= 0
rm= 1
What is the relative charge and relative mass of an electron
rc= -1
rm= 1/2000
What does the mass number tell us
the number of protons and neutrons in the nucleus
What does the atomic number tell us
the number of protons in the nucleus
What is the charge of all atoms
neutral
What are ions
they have a different number of electrons and protons
What is a negative ion
an ion that has gained electrons to have a full outer shell to form a more stable ionic compound
What is a positive ion
an ion that has lost electrons to gain a full outer shell to form a more stable compound
What are isotopes
elements with the same number of protons but a different number of neutrons
What was John Dalton’s interpretation of the atom
atoms were spheres and each elements is made up of different spheres
What was J.J’s interpretation of the atom
discovered the electron and created the plum pudding model, discovered it wasn’t solid and was made up of other particles
What was Rutherford’s interpretation of the atom
discovered the nucleus and that it was very small and positively charged, also concluded the atom was mainly made up of empty space he called a negative cloud
What was Rutherford’s evidence for his model
used the gold leaf experiment in which he fired positive alpha particles at a thin gold leaf, most travelled through (empty space) but some deflected back (hit a small positive nucleus
What was Bohr’s interpretation of the atom
discovered the cloud of electrons would collapse into the positive nucleus so proposed there were energy shells
What was Bohr’s evidence for his interpretation of the atom
when EM radiation is absorbed, electrons mov between shells and emit thus radiation when electrons move down to lower energy shells
Describe the atomic model today
electrons don’t have the same energy in shells, sub shells are present which explains ionisation trends
Define the term relative atomic mass
the weighted mean mass of an atom of an element compared to 1/12th of the mass of an atom of carbon-12
Define the term relative isotopic mass
the mass of an atom of an isotope compared to 1/12th of the mass of an atom of carbon-12
What does m/z represent on a mass spectra graph
the mass of an isotope divided by its charge
what is the equation for relative atomic mass
(abundance of A) x (abundance B) / total abundance
