Question

The atomic number of an element is 12. Based on its electron arrangement, which of the following explains its correct position in the periodic table?

A)Group 3, because it has two electrons in the 3p orbital.
B)Group 2, because it has two electrons in the 3p orbital.
C)Group 3, because its last electron is in the 3p orbital.
D)Group 2, because its last electron is in the 2p orbital.

Answer 1

Answer: Group 2, because it has two electrons in the 3s orbital.

Step-by-step explanation:

Electronic configuration represents the total number of electrons that a neutral element contains.Thus for element with atomic number 12 contains 12 electrons.

The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration is :

`1s^22s^22p^63s^2`

As the element belongs to s-block, as last electron enters s orbital, its group number = Number of valence electrons (or outermost shell electrons), which is 2.

Thus group number is 2.

Answer 2

Answer;

D)Group 2, because its last electron is in the 2p orbital.

Explanation

An atom with 12 electrons has an electronic configuration of 1s22s22p63s2.

The element belongs to group two of the periodic table and period 3, since it has three energy levels.

It is in group two since it has two electrons in the outer most energy level.