1. PbO is a possible formula units, since O has charge of 2- and Pb can have a charge of 2+ or 4+, if it uses the 2+ ion, the charges will balance out to form PbO. Li+ and B(3-) would have Li3B, Al(3+) and Pb(2+) are both positive charges and would not balance out, Cl- and O(2-) are both negative charges and would not balance out.
2. Iodine is a halogen, so it has a charge of -1. Calcium is an alkaline earth metal in Group 2, so it has a charge of 2+. Therefore, if they were to form a formula unit, the resultant would be CaI2 (2 iodine atoms of 1- charge are needed to balance out the 2+ charge on the calcium atom).
3. Strontium is an alkaline earth metal with a charge of 2+, while phosphorus has a charge of 3-. Therefore, to balance the charges out, we would need 3 atoms of strontium and 2 atoms of phosphorus. This would give the formula unit of Sr3P2.
A. T A A G C T A C G
B. A T G C C T A G C
The effect differs. It could produce a different amino acid in the sequence because the corresponding codon has changed. It could also prevent the production of the originally intended sequence by changing one of the amino acids of a "start" codon (aka AUG) or extend the protein's sequence by modifying a "stop" codon (UAA, UAG, UGA or UGG), producing a new protein that might be useless or have different effects on the cell.
