ACTINIDES

Periodicity

• Actinides is taken here to mean the 15 Elements from Actinium (Ac) to Lawrencium (Lr)

  q.v. argument as to whether Ac or Lr is the first 4^th Transition Series element

• Electronic subshells are filled in a manner analagous to the lanthanide series

Ac

Th

Pa

U

Np

Pu

Am

Cm

Bk

Cf

Es

Fm

Md

No

Lr

Z

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

M(g)

6d7s2

6d27s2

5f26d7s2

5f36d7s2

5f46d7s2

5f67s2

5f77s2

5f76d7s2

5f97s2

5f107s2

5f117s2

5f127s2

(5f137s2)

(5f147s2)

(5f146d7s2)

M+(g)

7s2

6d7s2

5f27s2

5f37s2

5f57s?

5f67s

5f77s

5f77s2

5f97s

5f107s

5f117s

(5f127s)

(5f137s)

(5f147s)

(5f147s2)

M2+(g)

7s

5f6d

5f26d

5f36d?

5f5?

5f6

5f7

5f8

5f9

5f10

5f11

(5f12)

(5f13)

(5f14)

(5f147s)

M3+(g)

5f

5f2

5f3

5f4

5f5

5f6

5f7

5f8

5f9

5f10

(5f11)

(5f12)

(5f13)

(5f14)

M4+(g)

5f

5f2

5f3

5f4

5f5

5f6

5f7

5f8

(5f9)

(5f10)

(5f11)

(5f12)

(5f13)

• i.e. the Actinides are the second row of the f-block (5f series)

  The Actinide Concept of Seaborg - proposed only in 1944

  • prior to the synthesis of trans-uranium elements only the chemistries of Th and U were much studied ~ leading to assignment as a 4^th transition series elements