Name: _________________________________ Date: _______ Period: _____
Periodic Trends
Description
In this activity you are going to create graphs of illustrating the major periodic trends found in the modern periodic table.
Below is a chart that contains information for the first 20 elements of the periodic table. You need to create a chart
comparing the atomic number with one of the sets of data. You will plot the atomic number on the x-axis and the
property, ex: atomic radius, on the y-axis. You will create 3 graphs each on a separate sheet of paper.
Each graph must include:
 A proper title, labeled axes with consistent spacing and units for both axes
 Each data point labeled with the element symbol. (ex. Li)
 Data points should be connected by lines.
 Colored lines representing each period (ex: period 1 H, He would be yellow, period 2 Li, Be, B, C, N, O, F, Ne
would be green, etc.). Make a key matching your chosen colors with the period.
Graph 1: Atomic # (x-axis) vs. Atomic Radius (y-axis)
Graph 2: Atomic # (x-axis) vs. 1st Ionization Energy (y-axis)
Graph 3: Atomic # (x-axis) vs. Electron Affinity (y-axis)
Element
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Atomic
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Atomic Radius (pm)
53
31
167
112
87
67
56
48
42
38
190
145
118
111
98
88
79
71
220
180
1st Ionization Energy
(kJ/mol)
1312
2372
520
899
801
1086
1402
1314
1681
2081
496
738
578
787
1012
1000
1251
1521
419
590
Electron Affinity
(kJ/mol)
-73
0
-60
240
-27
-122
0
-141
-328
0
-53
230
-44
-134
-72
-200
-349
0
48
2
Glossary
1. Ionization Energy - this is defined as the amount of energy needed to remove an electron from an atom. The
force attracting the electron increases as size decreases and as the positive charge increases.
𝑴 → 𝑴+ + 𝒆 −
2. Electron Affinity - this is defined as the amount of energy required to add an electron.
𝑿 + 𝒆 − → 𝑿−
3. Reactivity - this is defined as how readily an atom reacts. For metals this is based on ionization energy where the
most reactive metals are those with the lowest ionization energies. For nonmetals this is based on electron affinity
where the most negative electron affinity is the most reactive. This has to do with the fact that metals form
positive ions and nonmetals for negative ions.
Name: _________________________________ Date: _______ Period: _____
Analysis
1. Are there any elements that do not fit the periodic trends? Where are they in the periodic table? What
properties do not fit the periodic trends? Why are they different?
Atomic Radius
2. Define atomic radius in your own words.
3. What is the trend as you move down a group (column)? (think about the number of shells) Why? What is the trend
as you move across a period (row)? (think about the number of protons and number of electrons in that shell) Why?
4. Arrange the following atoms in order of increasing atomic radius: potassium, carbon, rubidium, iodine, fluorine,
and lithium. Explain your order.
5. When an atom loses an electron, what is its charge? What do you think happens to the size of the atom? Why?
6. When an atom gains an electron, what is its charge? What do you think happens to the size of the atom? Why?
7. Arrange the following ions in order of increasing atomic radius: S2-, Cl-, Ar, K+, Ca2+, and Br -. Explain your order.
Ionization Energy (potential)
8. Define ionization energy in your own words.
9. What is the trend as you move down a group (column)? Why? What is the trend as you move across a period (row)?
Why?
Name: _________________________________ Date: _______ Period: _____
10. Arrange the following atoms in order of increasing ionization energy: lithium, oxygen, magnesium, strontium,
chlorine, and tellurium. Explain your order.
11. Using an activity series, what can you deduce about the relationship between ionization energy and reactivity of
metals?
Denisty
12. Define density in your own words.
13. How does density change as you move down a group (column)? Why? How does density change as you move
across a period (row)? Why?
14. Some elements are found only in the gas state, for example Hydrogen is always found as, H2. How does the density
of a solid compare with the density of a gas? Where is this seen in the periodic table aside from Hydrogen? How are
the trends affected?
Melting and Boiling Point
15. Define melting and boiling point in your own words.
16. How do the boiling points and melting points change as you move down a group (column)? Why? How do the
boiling points and melting points change as you move across a period (row)? Why?