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Electrons and Electron Arrangement. General info on electrons. Electrons have a negative charge A neutral atom has the same number of electrons as protons. The mass of an electron is extremely small. Approximately 2000 electrons = the mass of one proton.
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General info on electrons • Electrons have a negative charge • A neutral atom has the same number of electrons as protons. • The mass of an electron is extremely small. Approximately 2000 electrons = the mass of one proton. • The electrons determine the size of the atom. The nucleus determines the mass of the atom. • Electrons spin around the nucleus in pairs in orbitals. These orbitals make up the electron cloud.
General info on electrons continued • The definition of an orbital: A 3 dimensional space with a high probability of finding a pair of electrons. • The 2 electrons which make a pair, spin in opposite direction from each other in the orbital.
Electron arrangements (configurations) • The electrons of any atom are very well organized. The first level of organization is the energy levels. • Every atom’s electron cloud consists of 7 energy levels or shells. • Each energy level (e.l.) has a specific energy requirement. For example, electrons in the first e.l. have less energy than electrons in the second e.l. • Although all atoms have 7 energy levels, these levels may not be completely filled with electrons or have any electrons at all.
Energy levels • Each energy level has a maximum amount of electrons that it will contain. • Level one: holds 2 electrons • Level two: 8 electrons • Level 3: 18 electrons • Level 4: 32 electrons • Levels 5-7: 32 electrons
Orbitals within energy levels • With in each e.l. there is further organization. There are specific orbitals.( remember an orbital contains a pair of electrons.) • The e.l.s and their orbitals with electrons are arranged as follows:
E.L. Orbitals total electrons • 1 s = 2 e- 2 • 2 s=2 e-, p=6 e- 8 • 3 s=2 e-, p=6e-, d=10e- 18 • 4 s=2e-, p=6e-, d=10e-, f=14e- 32
Electrons produce light • Electrons are capable of producing light when energy is supplied. • The electrons receive energy and are able to leave their ground state energy level and move to higher energy levels. • At the higher energy level, the electrons are unstable and so return to their original ground state releasing the energy absorbed in the form of light.
Electrons produce light continued. • This energy emitted corresponds to a particular wavelength and shows up as a line in the spectrum. • When electrons return to the first level (n=1) the series of lines occurs in the ultraviolet region as this involves the largest energy change. • When electrons drop to other levels different waves lengths of light are produced in the visible light range.
Each spectrum is unique for each element • Since every element has a unique valence electron arrangement, every element has a unique spectrum. • The energy released when an electron drops from one energy level to another is unique to each element, thus, giving a unique spectrum. • The spectrum for a given element can be used to identify the element such as a fingerprint can identify a human.
