Express the mass of the atoms and molecules in both standard notation and scientific notation. If necessary, round the numbers so the first factor goes only to the hundredths place.
• one iron atom
• one water molecule
• one silver atom
• one gold atom
• one platinum atom
• one uranium atom

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is