![]() ![]() Only photons of the same energy as the energy in the electron jump will be emitted. Light is not simply a continuous wave but is emitted as "packets" of light called photons. ![]() When the electron absorbs energy in an absorption spectra, the light of the particular wavelength is shown as a black line. When the electron emits energy in an emission spectra, it gives it off as a wavelength of light of a particular colour. When the electron moves between the energy levels, it emits or absorbs energy.This energy is emitted or absorbed as "packets" of light called photons. Elements can only occupy given energy levels and is said to be quantised. This spectra corresponds to wavelengths of the same energy level jump, hence, different elements have different spectra. Line spectra is produced when the element radiates light. This is because elements do not provide a continuous spectrum of light.Įmission Spectra and absorption spectra ![]() This light can be analysed and each element has its own spectra. In other words, the simple model cannot explain why matter is stable.ħ.1.4 Outline evidence for the existence of atomic energy levels Įlements emit light when given enough energy. Why didn't the electrons emit radiation and lose energy? How would they be kept in a constant orbit? Hence, the limitation of the simple model would be that the atom would decay quickly, as electrons would spiral into the nucleus. Rutherford's model was that around the small, highly charged nucleus, electrons orbited like planets around the sun. According to the theory of electromagnetism, an accelerated charge should radiate electromagnetic waves and thus lose energy. The alpha particle collided with the gold nucleus.ħ.1.3 Outline one limitation of the simple model of the nuclear atom įirstly, the simple model of the nuclear atom is that there is a small nucleus surrounded by orbiting electrons (there are no electron shells). Alpha particles are repelled by the nucleus, causing its path to deflect at an angle.Ī small percentage of the particles "bounced" back at an angle larger than 90º Most particles passed through the gold foilĪ small percentage of the particles deflected at 0º-90º This result suggested that atoms consisted mostly of empty space, with a small nucleus of high positive charge. ![]() Of those which were deflected, many were deflected through very large angles, and even straight back at the source. The results of the experiment were that the majority of alpha particles passed straight through. The alpha particle scattering experiment (by Rutherford/Geiger+Marsden) involved firing alpha particles at a sheet of very thin gold foil, and detecting where they went (with a screen). The Geiger-Marsden experiment supports the current nuclear model of the atom. The electrostatic attraction between the electrons and the nucleus keep the atom together.ħ.1.2 Outline the evidence that supports a nuclear model of the atom.The nucleus is orbited by "shells" of electrons.The nucleus is composed of protons (that have a positive charge) and neutrons (that have a neutral charge).The atom is spherical in shape composed of a small and dense nucleus.7.1 Atoms and their constituents Atomic structure 7.1.1 Describe a model of the atom that features a small nucleus surrounded by electrons. ![]()
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