Lesson Worksheet: Isotopes Chemistry • 10th Grade

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In this worksheet, we will practice defining and identifying isotopes of an element, listing some of their properties and uses, and calculating the relative atomic mass of an element from isotopic abundances.

Q1:

The “iso” in “isotope” is derived from the Greek word for “equal”. In what way are isotopes equal?

AThey have the same number of protons in their nuclei.
BThey have the same atomic radius.
CThey have the same mass number.
DThey have the same number of neutrons in their nuclei.
ETheir common ions have the same charge.

Q2:

Fill in the blank. Isotopes are atoms with the same number of protons but a different number of .

Aions
Bnuclei
Catoms
Dneutrons
Eelectrons

Q3:

An atom has 3 protons and 5 neutrons in its nucleus. Which of the following is an isotope of this atom?

AAn atom with 3 protons and 5 neutrons in its nucleus
BAn atom with no protons and 5 neutrons in its nucleus
CAn atom with 4 protons and 4 neutrons in its nucleus
DAn atom with 3 protons and 4 neutrons in its nucleus
EAn atom with 5 protons and 3 neutrons in its nucleus

Q4:

Which of the following is an isotope of magnesium-25?

AMagnesium-24
BMagnesium-25
CSodium-25
DTitanium-50
ESodium-23

Q5:

Which of the following isotopes is the heaviest?

ANeon-22
BBoron-11
CHydrogen-3
DSodium-21
EFluorine-17

Q6:

What does it mean if two atoms are described as isotopes?

AThey are different elements with the same atomic mass.
BThey have the same number of neutrons but different numbers of protons in their nuclei.
CThey have the same number of protons but different numbers of neutrons in their nuclei.
DThey are equally unstable.
EThey are chemically bonded together.