DSE Chem revision
Topic 6. Microscopic World II
A. Simple molecular substances with non-octet structures
-
recognise the existence of covalent molecules
with non-octet structures -
draw the electron diagrams of some non-octet
molecules such as BF3, PCl5 and SF6
B. Shapes of simple molecules
-
Predict and draw three-dimensional diagrams to represent shapes of
(i) molecules with central atoms obeying octet rule; and (ii) molecules with central atoms not obeying octet rule and with no lone pair of electrons (such as BF3, PCl5 and SF6)
C. Polarity of bond and molecule
-
define the electronegativity of an atom
-
describe the general trends in the electronegativities of the main group elements down a group and across a period in the Periodic Table
-
explain the sharing of electrons in covalent bonds leads to non-polar and polar covalent bonds
-
identify the partial charges of polar molecules such as HF, H2O, NH3 and CHCl3
-
explain the polar nature of molecules such as HF, H2O, NH3 and CHCl3 and non-polar nature of moleules such as CH4 and BF3 with reference to electronegativity, polarity of bond and molecular shape
D. Intermolecular forces: van der Waals’ forces and hydrogen bonding
-
explain the existence of van der Waals’ forces in non-polar and polar covalent substances
-
state the factors affecting the strength of van der Waals’ forces between molecules
-
compare the strength of van der Waals’ forces with that of covalent bonds
-
describe the formation of hydrogen bonding as exemplified by HF, H2O and NH3
-
compare the strength of van der Waals’ forces with that of hydrogen bonding
-
understand the effect of hydrogen bonding on properties of substances such as water and ethanol
E. Structures and properties of ice
-
describe the structures of ice
-
state and explain the properties of ice in terms of its structures and bonding
#dse chem #dse chem 補習 #化學補習 #化學私補 #專補化學 #dsechem