Question

pls help answer the question ​

Answer 1

Questions

Write the electronic configuration of the element

$\sf { {}^{35} { \large{A}}_{17}}$

a) Valency of the element ?

b) type of valency with which the element combines ?

c) write the formula of the compound eventually formed when combined with Calcium ?

Answers :

$\sf { {}^{35} { \large{A}}_{17}}$

The electronic configuration of an element will be written based on its atomic number rather than atomic mass.

Electronic configuration is the arrangement of electrons in the atomic orbits or shells.

Atomic number is the number of protons or electrons in that atom.

Given element ! (element is unknown)

$\sf { {}^{35} { \large{A}}_{17}}$

Here,

The subscript represents the atomic number.

The superscript represents the atomic mass.

Atomic number (z) = 17

Electronic configuration = 2,8,7 (K,L,M)

_________________________________

The number of valence electrons are 7 but inorder to reach the nearest inert gas configuration it needs one more electron

valence electrons are the electrons in the outermost shell.

So,

Valency of A is 1 as it needs 1 more electron.

Hence,

Valency of the element is 1.

____________________________________

Since,

The valency is 1 it is called as monovalent.

This element will combine with those elements who are ready to lose one electron inorder to attain stability.

(Eg : Sodium and Chlorine )

______________________________________

Element

$\sf { {}^{40} { \large{Ca}}_{20}}$

Element - Calcium (Ca)

Atomic number : 20

Electronic configuration : 2,8,8,2

Since, the valence electrons are 2

Valency of Calcium = 2

Now, let's find out the formula of compound when the element A combines with Calcium!

Here we will only consider the valency and it will be written as a superscript !

A¹ Ca²

By Criss cross method

Valency's get interchanged!

$\sf{\large{ A_{2} {Ca}_1 }}$

Formula of the compound

$\red{\sf{\large{ A_{2} {Ca}_1 }}}$

_____________________________________

Answer 2

1. Electronic configuration = 2,8,7 (K,L,M)
2. Valency of the element is 1.
3. A2 Ca1