Connect the group to the configuration. pleas help !!

Explanation:

The group number in the periodic table represents number of valence electrons of the elements in a certain group.

Group 1 : 2,8,1

Group 2 : 2,8,8,2

Group 3 : 2,8,3

Group 4: 2,4

Group 7 : 2,8,7

 2, 8 7                7 valence electrons        Group 7

 2, 8 , 1              1 valence electrons         Group 1

 2 8 3               3 valence electrons         Group 3

  2  4               4 valence electrons         Group 4

 2 8 8 2            2 valence electrons         Group 2

Explanation:

The valency of an electronic configuration of an atom can be used to determine the group an element belongs.

The valency is the number of outermost shell electrons an atom contains.

 So;

 2, 8 7                7 valence electrons        Group 7

 2, 8 , 1              1 valence electrons         Group 1

 2 8 3               3 valence electrons         Group 3

  2  4               4 valence electrons         Group 4

 2 8 8 2            2 valence electrons         Group 2