SP4b Atomic Models Flashcards
What did the plum pudding model show?
.positive charge spread out
.atom is shape of a ball
What did the nuclear model show?
.orbiting electrons
.mostly free space
.nucleus
.accommodated alpha particle scattering results
.concentrated positive charge
What did the nuclear model and plum pudding model both show?
.positive charge
.accommodated discovery of the electron
.electrons
What is an ion?
a charged particle (it is positively charged if it has fewer electrons than protons).
Explain the relationship of the distance of an orbit from the nucleus, and energy.
each orbit is at a different energy level, the further from the nucleus, the more energy they have. As you move out from the nucleus, the energy levels get closer together, so the difference in energy gets smaller.
What happens when an atom absorbs just enough energy?
an electron can move to a higher orbit - excitation. This only occurs for a tiny fraction of a second.
What happens when an electron returns to a lower orbit?
the atom emits energy as visible light of a particular wavelength - de-excitation.
Electrons can make different changes, what does each different change produce?
a different wavelength of EM radiation.
What does high energy (big) jumps result in?
.high frequency
.blue light
What does low energy (small) jumps result in?
.low frequency
.red light
How did Bohr further develop the nuclear model of the atom?
it became evident to him that electrons in atoms can only exist at certain energy levels or discrete orbits.
Explain ionising radiation.
.an atom can gain so much energy that electrons jump completely out of the atom - ionisation
.radiation that causes atoms to gain this much energy is called ionising radiation
