Atomic Radius Graphing Activity

advertisement

Name Date Period

Introduction to Periodic Trends

Objective: You will investigate the group and period trend for atomic radius or the size of the atom.

Background Information: Atomic radius is a measure of an element’s size. To determine the atomic radius, it is generally considered to be the distance between the nucleus and the boundary of the surrounding electron cloud.

Pre-Lab Questions

1.

What is a group or family on the periodic table?

2.

What is a periodic on the periodic table?

Procedure

1.

Generate a graph of atomic radius versus atomic number for the first eighteen elements using the data below.

Be sure to label your axes and give your graph an appropriate title.

Graph

Element

Name hydrogen helium lithium beryllium boron carbon nitrogen oxygen fluorine

Atomic

Number

1

2

3

4

5

6

7

8

9

Atomic Radius

(in pm)

37

32

152

111

88

77

70

66

64

Element

Name neon sodium magnesium aluminum silicon

phosphorus sulfur chlorine argon

Atomic

Number

10

11

12

13

14

15

16

17

18

Atomic Radius

(in pm)

70

186

160

143

117

110

104

99

94

______________________

200

180

160

140

120

100

80

60

40

20

0

0 5 10 15

____________________________________

20

Analysis

1.

Highlight the elements of the third period in pink or yellow. What happens to the atomic radius or the size of the atoms as you move across the period from left to right? Explain why in one complete sentence.

2.

Circle the first two elements in the alkaline earth metal family in blue or green. What happens to the atomic radius or the size of the atoms as you move down the group? Explain why in one complete sentence.

3.

Using the information above, predict which element would be larger: Ca or K? Justify your answer.

4.

Using the information above, predict which element would be larger: Na or K? Justify your answer.

Download