Atomic Structure & Periodicity
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| development of quantum mechanical model of atom | ||
| electromagnetic radiation (all forms travel at speed of light in a vacuum) | ||
| distance between two consecutive peaks number of waves per second that pass through a point ...are inversely related | ||
| gamma rays --> visible light --> radio waves short wavelength... to... long wavelength high frequency... to... low frequency | ||
| light is both a particle and a wave light is energy energy is quantized (occurs in discrete units) so, light is quantized photons = small pieces of light | ||
| are directly related | ||
| continuous spectrum: white light = all the colors of the visible spectrum atomic spectrum: each element gives off its own characteristic colors, which can be used to identify the atom line spectrum or emission spectrum: unique to each element *line spectrum is important because it shows that only certain energies are allowed for the electron of the H atom *so, energy of electron is quantized | ||
| problem w rutherford's model... why don't electrons fall into the nucleus? --> electron in H atom moves around nucleus only in certain circular orbits to calculate energy of H electron: E=-2.178 J(z^2/n^2) z = nuclear charge and n = energy level | ||
| AKA electron cloud model schrodinger's equation describes the energy and position of electrons in an atom. it is a mathematical model and includes energy levels for electrons. it tells us the probability of finding an electron a certain distance from the nucleus. ELECTRONS DO NOT ORBIT NUCLEUS an orbital is a region where there is a high probability of finding an electron | ||
| -we cannot know both the momentum and the position of a particle at a given time -the more we know about one, the less we know about the other | ||
| -used to describe properties of orbitals | ||
| energy level of orbital integral values 1,2,3... | ||
| shape of orbital integral values 0 to n-1 0 for s orbital, 1 for p orbital, 2 for d orbital, 3 for f orbital | ||
| orientation of orbital integral values l to -l (including 0) | ||
| spin state of electron values of +1/2 or -1/2 | ||
| can hold a max of 2 electrons degenerate orbitals = orbitals that have the same energy ex) 2p orbitals. all 3 have the same energy | ||
| s (1) spherical p (3) dumbbell d (5) 4 clovers and 1 dumbbell w doughnut f (7) 4 double clovers and 3 dumbbells w 2 doughnuts | ||
| # shapes max # electrons starts at energy level s 1 2 1 p 3 6 2 d 5 10 3 f 7 14 4 | ||
| only s-orbital 2 electrons total 1s^2 | ||
| s and p orbitals 8 electrons total (2 in s, 6 in p) 2s^2 2p^6 | ||
| s p and d 18 electrons total | ||
| s p d and f 32 electrons total | ||
| energy level, sub-level, # of electrons | ||
| electrons enter lowest energy orbitals first | ||
| orbitals can hold up to 2 electrons (w opp. spins) | ||
| when electrons occupy orbitals of the same energy, they don't pair up until they have to | ||
| half-filled levels have lower energy, making them more stable this changes filling order examples are Cr and Cu transition metals tend to lose s electrons first, then d when becoming ions ex) Cu+ is [Ar] 3d^10 Cu2+ is [Ar] 3d^9 |