Name: ______________________________
Date: _______________
Exploring the Periodic Table
The Periodic Table was first published in 1869 by a Russian scientist named Dmitri
Mendeleev. There were about 55 known elements at that time, and Mendeleev began to notice
patterns in their properties when he arranged them a certain way. Originally Mendeleev arranged
the elements in order of increasing atomic mass but scientist in the 1900s realized that it was more
accurate to arrange them in order of increasing atomic number. An element’s atomic number is
based on how many protons it has in its nucleus. Neutral atoms have the exact same number of
protons and electrons. Each square on the periodic table tells us certain things, the element’s
name, the one or two letter chemical symbol, the atomic number, and the atomic mass. The
atomic mass is the average mass of one atom of the element. It can also be used to help us
determine how many neutrons are in each atom of that element if we use the formula atomic
mass – atomic number = number of neutrons. Each row in the periodic table is called a period.
Each column is called a group or family. And just like members in a real family, each group
shares certain characteristics. The periodic table is also divided into three main groups: metals,
nonmetals, and metalloids, which has properties of both metals and nonmetals. Today’s periodic
table has 118 named elements.
True or False
If the answer is TRUE, write TRUE on the line. If the answer is FALSE, replace the underlined
word with one that makes the sentence correct. Write the new word on the line.
___________________1. The modern periodic table organizes elements based on their atomic
mass.
___________________2. Elements in the same period have similar chemical properties.
Name: ______________________________
Date: _______________
Exploring the Periodic Table
___________________3. The atomic number is based on how many protons a single atom of
that element has.
___________________4. In a neutral atom, there are always the same number of protons and
neutrons.
___________________5. Protons + electrons = atomic mass.
Multiple Choice
Circle the letter of the best answer.
6. Dmitri Mendeleev arranged the elements in order of
a. Increasing atomic mass
c. Decreasing atomic mass
b. Increasing atomic number
d. Decreasing atomic number
7. If you know only the atomic number of an element, you also know the number of
a. Neutrons
c. Protons and electrons
b. Protons
d. Electrons and neutrons
8. The Periodic Table contains metals, nonmetals and
a. Soft metals
c. Non-metalloids
b. Elemental metals
d. Metalloids
9. An element with 7 electrons and 8 neutrons has an atomic mass of
a. 7
c. 15
b. 8
d. cannot be determined
Name: ______________________________
Date: _______________
Exploring the Periodic Table
Short Answer
Label each part of the square.
10.
11
36
11.
Na
Kr
12.
Sodium
Krypton
13.
23
84
10. ____________________
14. How many protons? ______
11. ____________________
15. How many neutrons? ______
12. ____________________
16. How many electrons? ______
13. ____________________
This element has 30 electrons
17. Atomic mass? ______
_____
Zn
Zinc
18. How many neutrons? ______
65
19. Atomic number? _______
20. This is an imaginary element. However, even fictitious elements have to follow the rules.
What three things are wrong with the information provided in the square?
13
IE
__________________________________________________
__________________________________________________
Imaginarium
5
__________________________________________________
Name: ______________________________
Date: _______________
Exploring the Periodic Table