Calculations quiz

1. A sample of bromine contained the two isotopes in the following proportions: bromine-79 = 50.7% and bromine-81 = 49.3%. Calculate the relative atomic mass of bromine

2. Calculate the relative formula mass(Mr) of a molecule of bromine (Br₂)

3. How many electrons in the outer shell of group 5 elements?

4. State the steps for calculating empirical formula

5. State the mass and charge of a neutron

6. To determine the formula of a metal oxide by combustion, magnesium is heated in a crucible. Why is a lid used?

7. What is the atomic number of a beryllium atom?

8. What is meant by the term molecular formula?

9. A compound that contained 24.24% Carbon. 4.04% Hydrogen and 71.72% Chlorine and has a relative molecular mass of 99. Calculate the empirical formula and the molecular formula.