How do determine the no. of valence elctrons of an element in the Transition metals if we know their group and periods?

Asked by SHIVASIS MOHANTY | 7th Feb, 2014, 06:36: PM

Expert Answer:

The number of valence electrons of an element can be determined by the periodic table group (vertical column) in which the element is categorized. With the exception of groups 3–12 (the transition metals), the number within the unit's place identifies how many valence electrons may be associated with a neutral atom of an element listed under that particular column.

The periodic table of the chemical elements

Periodic table group

Valence
electrons

Group 1 (I) (alkali metals)

1

Group 2 (II) (alkaline earth metals)

2

Groups 3-12 (transition metals)

2* 4s shell is complete and cannot hold any more electrons.

Group 13 (III) (boron group)

3

Group 14 (IV) (carbon group)

4

Group 15 (V) (pnictogens)

5

Group 16 (VI) (chalcogens)

6

Group 17 (VII) (halogens)

7

Group 18 (noble gases)

8**

 

* The general method for counting valence electrons is generally not useful for transition metals. Instead the modified d electron count method is used.

** Except for helium, which has only two valence electrons.

Answered by  | 10th Feb, 2014, 04:18: PM

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