AS-Level Chemistry Cheat Sheet
This "cheat sheet" provides a guide to answering subjective questions in Paper 2 for AS-Level
Chemistry. Format your answers according to what is written in this webpage.
1. Comparison of atomic radius / IE
[Going down the group]
① Positive nuclear charge increases
② Electron shielding increases
③ Weaker nuclear attraction for outer shell e-
④ No. of e- occupied shells increases
⑤ Weaker nuclear attraction for outer shell e-
[Going across the period]
① Positive nuclear charge increases
② Electron shielding same
2. Comparison between melting / boiling point
① X is giant ionic / giant covalent / simple molecule and Y is __________
② Covalent / electrostatic forces of attraction / LDF / permanent dipole-dipole / hydrogen
bonding occurs between X atoms / ions / molecules and __________ acts between Y
③ More heat energy is required to break / overcome __________ bonds / forces in X than
__________ bonds / forces in Y.
④ Less energy required to remove e- from __________ than __________
⑤ More energy required to remove e- from __________
3. Discrepancies in IE
① IE is removed from p shell of higher energy level in Al
② Smaller nuclear attraction number
③ Spin-pair repulsion between 2 electrons in s
④ e- is removed from full orbital in s but half-filled 3p orbital in P.
⑤ Between Al & Mg
⑥ Between P and S
4. Describing Observations
① Steamy fumes - HCl gas
② Solid produced - product of reaction
