Bromine (Br) has two stable isotopes and 30 known unstable isotopes, the most stable of which is 77 Br with a half-life of 57.036 hours Standard atomic mass: 79.904(1) u Table. Bromine has two stable isotopes, 79 Br and 81 Br, having relative mass abundances of 50.686% and 49.314%, respectively (Eggenkamp and Coleman, 2000). Variations in isotopic composition are reported as δ 81 Br (SMOB), where SMOB is standard mean oceanic bromide. Isotopes of Bromine (click to see decay chain): 67 Br 68 Br 69 Br 70 Br 71 Br 72 Br 73 Br 74 Br 75 Br 76 Br 77 Br 78 Br 79 Br 80 Br 81 Br 82 Br 83 Br 84 Br 85 Br 86 Br 87 Br 88 Br 89 Br 90 Br 91 Br 92 Br 93 Br 94 Br 95 Br 96 Br 97 Br. Isotopes Two naturally existing isotopes of bromine exist, bromine-79 and bromine-81. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The longest decaying fission product is a bromine isotope (Br-87) which has a 55.72 sec half-life (decay constant) for beta decay into stable isotopes of Sr-87 and Kr-86. The second group of delayed neutrons with the 23-second half-life (decay constant) is mainly composed of iodine (I-137) which has a 22-sec half-life, and forms an excited.

Bromine consists of two isotopes with masses of 78.92 and 80.92 amu. What is the abundances of these two isotopes?

1 Answer

Isotopes#color(white)(XX)#mass(amu)#color(white)(X)#Isotopic abundance

Br-79#color(white)(XXXX)#78.92#color(white)(XXXXXXX)#? Software you have to download for mac.

Br-81#color(white)(XXXX)#80.92#color(white)(XXXXXXX)#?

#'average atomic mass'=('mass*%'+'mass*%'+'mass*%'..)#

Let x be % abundance of Br-79

Let 1-x be % abundance of Br-81

Br is 79. 904g/mol on the periodic table#color(orange)'(average atomic mass)'#

#79.904%=x+(1-x)#

#79.904%=(78.92*x)+(80.92*(1-x))#

#79.904%=(78.92x)+(80.92-80.92x))# Onenote classroom permissions.

#79.904%=78.92x+80.92-80.92x#

#79.904%=-2x+80.92#

#79.904%-80.92=78.92x#

#-1.016=-2x#

#x=0.508#

Bromine Isotopes

Use our x to find that % abundance of Br-79

#x*100%#

#0.508*100%#

#=50.8##'%##abundance'#

Use our x to find that % abundance of Br-79

#(1-x)*100%#

#0.492*100%#

#=49.2##'%##abundance'#

#:.# The % abundance of the isotope with a mass of 78.92 amu has a % abundance of 50.8% and the isotope with a mass 80.92 amu has a % abundance of 49.2%

Related questions

Isotopes of the Element Bromine

[Click for Main Data]

Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information.

Bromine 81

Isotopes With A Known Natural Abundance

WebElements Periodic Table » Bromine » Isotope Data

Known Isotopes

For questions about this page, please contact Steve Gagnon.