How many moles of bromine atoms are in 2.60 × 102 grams of bromine? 1. 0.0152 mol 2. 79.9 mol 3. 10.5 mol 4. 3.25 mol 5. 2.29 mol 6. 0.308 mol 7. 48.6 mol?

There are 3.25 mol of bromine atoms in 2.60 x 102 grams of bromine. I reached this answer by converting grams to moles. To do this, I divided the number of grams that I have of bromine by the weight of bromine. The weight of bromine is 80 grams. So my equation looks like this when it is all set up: 2.6 x 10^2 g/80g. The answer to the equation is 3.25 mol.

Moles  =mass/ molar  mass  of  the  bromine  atom
the  molar  mass of  bromine  atom  is  79.904g/mol
mass=2.60  x10^2
therefore  the  moles  of  bromine  atom=
2.60  x10^2g/ 79.904g/mol  =3.25gmoles(answer  4)

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer