2.05 Calculating average atomic mass ticket out the door

Front

What is average atomic mass?

Back

The weighted average of the masses of an element's isotopes, taking into account their relative abundances.

Front

How do you calculate average atomic mass?

Back

Multiply the mass of each isotope by its relative abundance (as a decimal), then sum these values.

Front

If 24.1% of isotopes have a mass of 75.23 amu, 48.7% have 74.61 amu, and 27.2% have 75.20 amu, what is the average atomic mass?

Back

74.92 amu.

Front

What varies between isotopes of an element?

Back

The number of neutrons and the atomic mass.

Front

What is the atomic number of an element?

Back

The number of protons in the nucleus of an atom, which determines the element's identity.

Front

What do isotopes of an element have in common?

Back

They have the same atomic number and number of electrons.

Front

Which isotope of lead is likely to be the most abundant if the average atomic mass is 207.2?

Back

Lead-207.

Front

What is an isotope?

Back

Atoms of the same element that have different numbers of neutrons.

Front

How many neutrons does Li-7 have?

Back

4 neutrons.

Front

What is the mass number of an isotope?

Back

The total number of protons and neutrons in the nucleus.