Question

An element has its electron configuration as 2,8,2.Now answer the following questions. a.What is the atomic number of this element? b.What is the group of this element? c.To which perioddoes this element belong? d.With which of the following elements would this element resemble?(atomic numbers are given in the brackets) N(7),Be(4),Ar(18),Cl(17)

Answer 1

A . 12
B . 2A group.
C . 3
D . Be (4)


hope it helps you dear friend

Answer 2

Answer:

The atomic number of this element is 12 . It belongs to II group and  3 period.  The resemble element is Be.

Explanation:

Given that,

The configuration = 2,8,2

(a). The atomic number of this element  :

The electronic configuration = 2,8,2

$2,8,2=1s^2,2s^2\ 2p^6,3s^2$

This element is Mg.

Therefore, The atomic number of this element is 12.

(b). The group of this element is second group because the last electron enters to s block.

Thus it is a s block element. For s block elements the group no is equal to the no of electrons the valence shell contains

(c). The element belongs to 3rd period because the last electron enters into the third energy level.

(d). Be is the resemble element of this element because the last electron is same in the electronic configuration.

The electronic configuration of Mg = 2,8,2

The electronic configuration of Be = 2,2

Hence, The atomic number of this element is 12 . It belongs to II group and 3 period.  The resemble element is Be.