begin mathsize 36px style 1 over lambda equals R Z squared open square brackets 1 over n subscript f squared minus 1 over n subscript i squared close square brackets end style

λ= Wavelength of the emmited light (electromagnetic rediation) in the vacuum ; R = Rydberg Constant (1.097x 107 m-1) ; Z = Number of proton in the nucleus of the element; nf = Principal quantum number of final state; ni = Principal quantum number of the initial state 

begin mathsize 48px style X subscript M equals open parentheses I E space plus thin space E A close parentheses divided by 2 end style

XM =Electronegativity of an element ; IE = Ionization Energy ; EA =Electron Affinity 

begin mathsize 36px style X subscript A minus X subscript B equals 0.102 square root of E subscript A B end subscript minus left parenthesis E subscript A A end subscript. E subscript B B end subscript right parenthesis to the power of 1 half end exponent end root end style

XA , XB = Electronegativity of element A and B , such that XA > XBEAA =Bond energy of the A-A bond; EBB =Bond energy of the B-B bond;

EAB =Bond energy of the A-B bond;

begin mathsize 48px style mu equals square root of n left parenthesis n plus 2 right parenthesis end root end style

μ = Magnetic Moment ;  n = Number of unpaired electron;

begin mathsize 48px style mu subscript e f f end subscript space equals space 2.83 space square root of capital chi subscript M T end root space B. M end style

μeff = Magnetic Moment ; XM = Molar Suseptibility ; T =Temperature ; B.M= Bohr Magneton

begin mathsize 48px style V subscript i n i end subscript S subscript i n i end subscript equals V subscript f i n end subscript S subscript f i n end subscript end style

Vini = Volume of the solution before dilution , Vfin = Volume the solution after dilution , Sini= Initial strength of the solution after dilution, Sfin= Final strength of the solution after dilution

begin mathsize 36px style N equals fraction numerator W subscript s o l u t e end subscript. n over denominator V. M subscript w end fraction end style

N=Normality of the Solution ; Wsolute = Weight of the Solute ; V = Volume of the solution;

Mw = Molecular Weight of the Solute; n = Equivalence Factor (basicity of an acid or acidity of a base/Number of electron transfer per mole reaction)

begin mathsize 48px style V subscript 1 S subscript 1 equals V subscript 2 S subscript 2 end style

V1 = Volume of the 1st solution , V2 = Volume of the 2nd solution , S1= Strength of the 1st solution, S2= Strength of the 2nd solution