# Structure of an Atom

1. What is the average atomic mass of zinc according to the following data? Use four decimal places in your answer, do not include units.

isotope name isotope mass percentage

Zinc-63 63.23456 27.66%

Zinc-65 65.03252 remainder

2. How many protons are in an element of 193Pt?

3. A marble is 1.8 cm in diameter. How many marbles would have to be lined up in a row to reach a length of 1.24 meter? Round to the nearest whole number, do not include units.

4. Assume iron has two naturally occurring isotopes, 56Fe (isotopic mass = 56.0013 amu) and 55Fe (isotopic mass = 55.0184 amu). Iron has an atomic mass of 55.85 amu. What is the percent abundance of iron-55?

5. Determine the average atomic mass of boron is the natural abundance of 10B weighing exactly 10.0129 amu is 80.1% and the natural abundance of 11B weighing exactly 11.0093 amu is 19.9%? Show all your work.

6. The compound, P4S10, is used in the manufacture of safety matches. What is its name?

phosphorus sulfide

phosphoric sulfide

phosphorus decasulfide

tetraphosphorus decasulfide

phosphorus sulfide

7. What is the formula for the ionic compound formed by calcium ions and sulfate ions?

Ca3S2

Ca(SO3)2

CaSO4

Ca2SO4

CaSO3

8. Which of the following is most likely to form an anion with a charge of -2?

lithium

calcium

sulfur

bromine

more than one will carry that charge

#### Solution Preview

1. Average mass of zinc=63.23456*0.2766+65.03252*(1-0.2766)= 64.5352

2. Proton number in an atom is determined by the element. Therefore, Pt has 78 ...

#### Solution Summary

The average atomic amass of zinc according to data is determined.