Understanding Atomic Weight

Which subatomic particle has a positive charge?

• Neutron

• Electron

• Proton

• Photon

What is the unit used to express the mass of protons and neutrons?

• Pounds

• Grams

• Daltons

• Kilograms

What does the atomic number of an element represent?

• Number of protons

• Number of electrons

• Number of neutrons

• Number of isotopes

Why is the atomic weight not a whole number?

• It includes the mass of electrons

• It is a weighted average of isotopes

• It is an arbitrary number

• It is rounded to the nearest integer

How is atomic weight different from atomic mass?

• Atomic weight is always a whole number

• Atomic weight is a weighted average of isotopes

• Atomic weight is for a single atom

• Atomic weight is measured in grams

What is the relationship between atomic weight and molar mass?

• They are different numbers

• They are the same number but represent different concepts

• Molar mass is always larger

• Atomic weight is always larger

What information is needed to calculate atomic weight?

• Only the atomic number

• Isotope masses and their abundances

• The chemical symbol

• The number of electrons

How do you convert abundance percentages to decimal form?

• Move the decimal point two places to the left

• Divide by 10

• Multiply by 100

• Add 0.5

What is the atomic weight of chlorine as calculated in the example?

• 34.96

• 35.45

• 36.97

• 37.00

If one isotope's abundance is known, how can you find the other?

• Divide by 2

• Multiply by 2

• Add 50%

• Subtract from 100%