Name
Date
Class
Metals
Chapter 9 Lesson 2
Read the passage and look at the tables below it. Then answer the questions that follow the tables.
More Properties of Metals
You have learned that elements in the same group of the periodic table have similar properties. For
example, the metals of group 1 are so reactive they do not exist uncombined in nature. The group 2
metals are also quite reactive.
The tables below show the atomic radius and reactivity of most of the metals in groups 1 and 2. The
more reactive a metal is, the more stars appear in the reactivity column. You might expect the atomic
radius of an element to be half its diameter. However, atoms do not have a definite surface, as a ball
does. An atom’s electrons are constantly moving around the nucleus in a region of space that has no
distinct edge. So, atomic radius is calculated as one half the distance between the nuclei of two identical
atoms. The unit of measurement is the picometer (pm). One picometer is equal to 0.000000000001
meter.
Group 1
Group 2
Period
Element
2
Li
3
Na
4
Atomic
Radius
(pm)
Reactivity
Rating
Period
Element
Atomic
Radius
(pm)
Reactivity
Rating
123

2
Be
89

157

3
Mg
136

K
203

4
Ca
174

5
Rb
216

5
Sr
191

6
Cs
235

6
Ba
198

1. How does the atomic radius change from top to bottom in Groups 1 and 2?
2. How does the atomic radius change from an element in Group 1 to an element in the same period in Group 2?
3. How does reactivity change from top to bottom in Group 1? Does the same pattern hold in Group 2?
4. How does reactivity change from an element in Group 1 to an element in the same period in Group 2?
5. What seems to be the relationship between atomic radius and the reactivity of the elements in Group 1 and Group
2?
6. Francium is the Group 1 element of Period 7. Infer how francium’s atomic radius compares to cesium’s. Do you
think francium is more or less reactive than cesium? Explain.