They start with the numbers u need to know in order to slove the problem and there has to be a story behind it
c. Isoleucine has a carbon “branched” closer to the alpha carbon than does leucine.
The structure of leucine is CH3CH(<u>CH3</u>)CH2CH(NH2)COOH.
The structure of isoleucine is CH3CH2CH(<u>CH3</u>)CH(NH2)COOH.
In leucine, the CH3 group is <em>two carbons away</em> <em>from</em> the α carbon; in isoleucine, the CH3 group is on the carbon <em>next to</em> the α carbon.
Thus, <em>isoleucine</em> has the closer branched carbon.
“One is charged, the other is not” is i<em>ncorrect</em>. Both compounds are uncharged.
“One has more H-bond acceptors than the other” is <em>incorrect</em>. Each acid has two H-bond acceptors — the N in the amino and the O in the carbonyl group.
“They have different numbers of carbon atoms” is <em>incorrec</em>t. They each contain six carbon atoms.
Explanation:
A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when the periodic table skips a row and a chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. The first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block. All of the period 3 elements occur in nature and have at least one stable isotope.[1]
