Organic Analysis Model Answers

Question 1

Why is second ionisation energy of sodium is greater than second ionisation energy of magnesium?

Answer 1

Na2+ requires loss of electron from a 2p orbital/2nd energy shell/2nd shell and Mg requires loss of electron from a 3s orbital/3rd energy level/3rd shell OR Na2+ loses electron from lower energy orbital
Less shielding in Na
electron closer to nucleus/more attraction of electron to nucleus in Na

Question 2

State and explain the trend in atomic radius across a period

Answer 2

Increasing nuclear charge/number of protons

Electrons in same shell or level/similar shielding

Question 3

Explain why sodium has a lower melting point than magnesium

Answer 3

Na fewer protons/smaller nuclear charge/fewer delocalised electrons
Na is bigger atom/ion
Smaller attraction between nucleus and electrons

Question 4

What is the fingerprint region and state how it is used to confirm the identity of organic molecules?

Answer 4

Fingerprint region is below 1500cm-1 in the spectra

The fingerprint region of the unknown molecule will be an exact match with the known compound