PERIODIC TRENDS IN ATOMIC RADIUS

In this activity, you will prepare a graph of atomic radius as a function of atomic number.  Using this graph, you will investigate the trends in atomic radius within a group and a period of the Periodic Table.

PROCEDURE:
1.  Label the horizontal (x) axis atomic number and the vertical (y) axis atomic radius.  Set up appropriate scales for the data provided below.  (Click here to learn how to set up appropriate scales for your data.)  Plot the data and join the points with a solid line.  Do not label each data point.

1

H

0.30

 

15

P

1.06

 

29

Cu

1.17

 

42

Mo

1.30

2

He

0.31

 

16

S

1.02

 

30

Zn

1.25

 

43

Tc

1.27

3

Li

1.23

 

17

Cl

0.99

 

31

Ga

1.26

 

44

Ru

1.25

4

Be

0.89

 

18

Ar

0.98

 

32

Ge

1.22

 

45

Rh

1.25

5

B

0.82

 

19

K

2.03

 

33

As

1.20

 

46

Pd

1.28

6

C

0.77

 

20

Ca

1.74

 

34

Se

1.17

 

47

Ag

1.34

7

N

0.74

 

21

Sc

1.44

 

35

Br

1.14

 

48

Cd

1.48

8

O

0.70

 

22

Ti

1.32

 

36

Kr

1.12

 

49

In

1.44

9

F

0.68

 

23

V

1.22

 

37

Rb

2.16

 

50

Sn

1.40

10

Ne

0.67

 

24

Cr

1.18

 

38

Sr

1.91

 

51

Sb

1.40

11

Na

1.54

 

25

Mn

1.17

 

39

Y

1.62

 

52

Te

1.36

12

Mg

1.36

 

26

Fe

1.17

 

40

Zr

1.45

 

53

I

1.33

13

Al

1.18

 

27

Co

1.16

 

41

Nb

1.34

 

54

Xe

1.31

14

Si

1.11

 

28

Ni

1.15

 

 

 

 

 

 

 

 

 Link to paper to graph this data

2.  Divide the graph into several sections by drawing vertical lines through the points that represent the noble gases.

ANALYSIS:
1.  What does each section of the graph represent with respect to the Periodic Table?

2.  Create two lists:
    (A) the symbols of the elements with the smallest atomic radius in each section
    (B) the symbols of the elements with the largest atomic radius in each section

CONCLUSIONS:

Within a period, as atomic number increases, atomic radius ____________________ because...

 

The ____________________ elements in a period seem to have similar atomic radii.  This is probably due to...

 

Within a group, as atomic number increases, atomic radius ____________________ because...

 

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