chemistry laboratory report Experiment 9

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E\PERIIIENT 9 prame Test, Atomic Structure and euantum Numtrers In this laboratory you will observe characteristic flame colors exhibited by certain :iT;'ffir}l#tJr::

leam the principles of atomic ,t*.tu.", electronic configuration,

-{pparatus: Nichrome wire spiral, Bunsen burner

chemicals: concentrated HCI(aq), 0.1 M Nacl, 0.1 M KCl, 0.1 M CaClz, 0.1 M SrClu,

Safety Precautions: Handle concentrated hydrochloric acid carefully since it is verycomosive' causing damage upon any contaci with the boJv, clothes or books. Avoid spills,splashes' and contact with .$1 a"v spills must u. r.rt uiiled with sodium carbonate. Ifany acid comes in contact with skin, immediately flood *lit *ut... Report any spill to1',our instructor immediately so it can be neutralized and cleaned up. wear safetyglasses/goggles to protect your eyes.

An element is a form of matter,nrrlIffi?il"ort;1fl* ,r,,o simpler substances bychemical means' It is made of tiny particles called u,o-* gu.h atom is composed of threefundamental particres.posrtivery ct r.ged protons, ,"gatir.ry charged electrons, anduncharged neutrons' The dense tentrai rril.r* of an ortom contains protons and neukonswith electrons moving around the nucleus at arelatively large distance. The number ofprotons in the nucleus of an atom of an element is the uto*i. number (Z) of theelement.The sum of the number ofprotons and the number orr.ri.om in the nucleus is the massnumber (A) of the atom. Thus the number of neutrons ir, * uro- is equar to thedifference between the mass number and the atomic n*u"r, i.e., (A - Z).Forany neutralatom the number of electrons is equal to the number "ip.o,o"r. The identity of anelement is determined by the atomic number. Atoms wiih identical atomic numbers butdifferent mass numbers are called isotopes.

An electron has both particle-like and wave-like properties. The energy of an electron inan atom is quantized' The behavior of each etect.oni, hya.og"., and other atoms can bedescribed by a wave equation. The solutions to the;;;;"rtion, called wave./unctionsor orbitals, predict the alowed energy states of an electr""';;;;;;; *iG *findingthat electron in a particular region oian atom. Each wave function has a set of threequanfum numbers: n, l, and mr.For the hydrogen atom, onry the first of these threenumbers is required to describe the energy of the electron, but all three are needed todefine the probability of finding the electron in a given region of space. The values of allthree quanfum numbers are integers but cannot be selecteJrandomly. The Principal Quantum Numb er, n = 1,213,, ..., n The principal quantum number n determin. th" .r".gy of an electron and is also ameasure of the most probable distance of the electrorifrom the nu"l"us. es , i*..ur".,