Lesson 6.1

Question 1

The number of electrons, protons, and neutrons determines the mass of an atom.

Question 2

is the mass of an atom expressed in atomic mass
units (amu).

Answer 2

Atomic mass (also called atomic weight)

Question 3

The standard in measuring the atomic mass of the other
elements was set to 12 amu, which is based on the atomic mass of carbon-12.

Question 4

Isotopes are atoms that have the same
number of protons and electrons but with a different number of neutrons. Thus, it also has
a different atomic mass.

Question 5

average weight of all isotopes in a normal
environment is called the

is a standardized number and is assumed to be true for most of the planet
Earth’s crust.

Answer 5

relative atomic mass.

Question 6

publishes suggested values, which are updated every year. It is
assumed that in a given sample, this value can be used for science and industry.

Answer 6

The International Union of Pure and
Applied Chemistry (IUPAC)

Question 7

When the natural percentage abundance is considered in calculating the weight of the
naturally occurring isotopes of an element, it is called an

is the sum of all naturally occurring isotopes of an
element multiplied to its natural percentage abundance. This is dependent on a
given sample.

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Answer 7

average atomic mass.

Question 8

(isotope mass)(percentage abundance)