WorksheetsIsotopes and percent abundance
Total questions: 19
Worksheet time: 13mins
Isotopes of an element have a different number of...
Protons
Neutrons
Electrons
Mass
Rubidium has two common isotopes, 85Rb and 87Rb. If the abundance of 85Rb is 72.2% and the abundance of 87Rb is 27.8%, what is the average atomic mass of rubidium?
85.468 amu
37 amu
85.6 amu
86.4 amu
An isotope has three forms. 10% have a mass of 4 amu, 20% have a mass of 5 amu and 70% have a mass of 6 amu.
Based on the percentage of abundances above, the average atomic mass will be closest to...
3 amu
4 amu
5 amu
6 amu
None of the above
What is the weighted average of the masses of all naturally occurring isotopes of an element called?
isotope
ion
average atomic mass
radioactive
In isotopic notation, what number is on top?
mass number
atomic number
element
isotope number
In isotopic notation, what number is on the bottom?
mass number
atomic number
element
isotope number
An unknown element has three isotopes. Given the abundances and relative masses, determine (from the periodic table) which element it is.
Abundances | Relative masses
0.005% | 234.04 amu
0.720% | 235.04 amu
99.275% | 238.05 amu
HINT: You do NOT need to calculate anything here.
Uranium (#92, Atomic Mass: 238.03 amu)
Fluorine (#9, Atomic Mass: 19.00 amu)
Mercury (#89, Atomic Mass: 200.59 amu)
Polonium (#84 209 amu)
Element Z has 2 natural isotopes. One isotope has a mass of 15.0 amu and a relative abundance of 30%. The other isotope has a mass of 16.0 amu and a relative abundance of 70%. Estimate the average atomic mass for this one element.
15.0 amu
16.0 amu
15.7 amu
16.9 amu
Which of the following are isotopes?
a) 14 7X b) 14 6X c) 15 7X d) 15 8X
a) and b)
a) and c)
c) and d)
a) and d)
