chapter 2 Flashcards
what is an atom composed of?
protons, neutrons, electrons
what is mass number?
the number of protons + number of neutrons
what is atomic number?
the number of protons
what are ions?
charged particles that are forms when an atom loses or gains electrons
what is a positive ion
cation
what is a negative ion?
anion
what are isotopes
different atoms of the same element with different mass numbers
what is relative atomic mass?
the average of the masses of the isotope relative to carbon 12
what are electrons arranged into?
energy levels (shells)
what does the hydrogen emission spectrum look like?
sharp bright lines in a black background
what is ionisation energy?
energy required to remove one electron from each atom in one mole of gaseous atoms under standard conditions
where do lines converge in an emission spectrum?
converge at higher energy levels
why is second ionisation always higher than the first?
its a positive ion that will attract a negatively charged electron, once an electron has been removed from an atom there is less repulsion between remaining electrons
