Biochem Revision - Week 1 Chemical Elements

Question 1

What are the two models of atomic structure? What is an atomic orbital?

Answer 1

a) Planetary model with electron orbit rings

b) Atomic orbital model (electron cloud) where the position of e- are depicted in e- clouds that are denser where it is more likely to encounter e-

Question 2

Define isotope, atomic mass, isomer, radicals/free radicals,
polarity and miscibility

Answer 2

Isotope - Two atoms of the same element may differ in their # of neutrons. Isotopes can be identified using a subscript equal to the sum of the number of protons and neutrons, before the element’s symbol

Atomic mass - Measured in Daltons

Isomer - Different arrangements of structural formulas

Radical - Molecules and ions with 1 or more unpaired e- (can also be charged radicals such as superoxide - an O2 with an extra e-)

Polarity - some elements attract bonding e- more strongly than others, creating an uneven distribution of e- and partially charged poles

Miscibility - polar/polar mix, nonpolar/nonpolar mix, opposites do not

Question 3

What is an example of a buffer system?

Answer 3

Pairs of conjugate acids and bases are called buffer systems

High buffer capacity of living organisms mean that there is a large quantity of strong acid/base that needs to be added to one L of solution in order to change the pH by one unit.