Target questions

Target questions

1. Isotopes are atoms with the same number of protons but a different number of neutrons

2. Why the Ar of an element if different to the one you would calculate (TOF)?

   • The Ar in the periodic table takes into account other isotopes-that were not present in the mass spec sample.

3. Why do isotopes of an element have the same chemical properties?

   • Because they have the same electron configuration/same amount of electrons in their outer shell.

4. Why are some particles with the same mass a velocity deflected by different amount in the same magnetic field?

   • The particles have different m/z values.

5. Explain how the detector in a mass spectrometer enables the abundance of isotopes to be measured.

   • 1) Ions hit the detector and cause a current. 2) the bigger the current, the more of the isotope/current is proportional to its abundance

6. Relative atomic mass: average mass of one atom, 1/12 of a carbon atoms

7. Which isotope is deflected the most in the magnetic field of a mass spectrometer?

   • On peak that has the lowest m/z value (on the graph)

8. Explain why the iodine has a higher melting point than fluorine.

   • Iodine has more electrons and there are more stronger VDWs between molecules of iodine than fluroine.

9. Why is the melting point of NaI lower than the melting point of NaBr?

   • Iodine is a bigger ion, so there is less attraction to Na+ ion

10. State and explain the general trend in 1st Ionisation energies for period 3 elements from aluminium to argon.

    • Ionisation energies increase. This is because their is an increase is nuclear charge. This means that the shielding stays the same/smaller atomic radius.

11. State a physical property that allows them to be separated from a mixture by fractional distillation.

    • Having different boiling points

12. Uses of ethene?

    • Ripening fruit