Which group of atomic numbers represents the elements of the same group.
Which group of atomic numbers represents the elements of the same group.
The correct option is A 12, 20
Answer: Correct option (A)
Definition.
Valence electron: The number of electrons present in the last shell of an atom is known as the valence electron.
Electronic configuration.
Atomic number electronic configuration
K, L, M, N
12 2, 8, 2
20 2, 8, 8, 2
6 2, 4
13 2, 8, 3
8 2, 6
17 2, 8, 7
3 2, 1
15 2, 8, 5
Explanation of correct option.
The elements which have the same valence electron belong to the same group. Here elements with atomic numbers 12 and 20 both have 2 valence electrons in the last shell, therefore they belong to the same group.
Explanation of Incorrect option.
Atomic numbers present in other options have different electrons in their last shell, as you can see from the table, therefore they do not belong to the same group.
Conclusion.
Elements with atomic numbers 12 and 20 both have 2 valence electrons in the last shell, therefore they belong to the same group. Hence option(A) is correct.
12, 20
Answer: Correct option (A)
Definition.
Valence electron: The number of electrons present in the last shell of an atom is known as the valence electron.
Electronic configuration.
Atomic number electronic configuration
K, L, M, N
12 2, 8, 2
20 2, 8, 8, 2
6 2, 4
13 2, 8, 3
8 2, 6
17 2, 8, 7
3 2, 1
15 2, 8, 5
Explanation of correct option.
The elements which have the same valence electron belong to the same group. Here elements with atomic numbers 12 and 20 both have 2 valence electrons in the last shell, therefore they belong to the same group.
Explanation of Incorrect option.
Atomic numbers present in other options have different electrons in their last shell, as you can see from the table, therefore they do not belong to the same group.
Conclusion.
Elements with atomic numbers 12 and 20 both have 2 valence electrons in the last shell, therefore they belong to the same group. Hence option(A) is correct.
