Question

The atomic numbers of three elements, X, Y and Z are 9, 11 and 17 respectively. Which two of these elements will show similar chemical properties? Why?(Delhi - 2011)

Answer 1

Explanation:

Atomic no. of X = 9

Electronic configuration = 2,7

Valence electrons = 7

Valency of X=1

Atomic no. of element Y = 11

Electronic configuration of Y = 2,8,1

Valency of Y= 1

Atomic no. of element Z = 17

Answer 2

Answer:

The chemical characteristics of the elements X and Z will be similar.

Explanation:

The element X has an atomic number of 9 and has 7 electrons in the outermost shell

• This element can obtain one electron more easily than it can lose seven. As a result, the valency is -1.

• The electronic configuration is  $1s^22s^22p^5$ and this element belongs to the p block.

• It is a member of the 17th group.

Y is an atomic number 11 with one electron in the outermost shell.

• As a result, one electron can be lost to achieve an octet. As a result, the valency is 1.

• The electronic configuration is  $1s^22s^22p^63s^1$ and this element belongs to the s block.
• The group to which belongs is 1.

Z has an atomic number of 17 and an outermost shell with 7 electrons.

• To achieve octet, this element could gain one electron. So the valency is -1.

• The electronic configuration is $1s^22s^22p^63s^23p^5$
• It's part of the p block, and it's in the 17th group.

All halogens have comparable chemical characteristics and are reactive non-metals.