Question

028.
An element 'X' has atomic number 17 react with an element 'Y' atomic number 20 to form a compound.
Write the group number of element 'X' and 'Y',
(ii) Classify 'X' and 'Y' as metal and non-metal.
(iii) What will be the nature of oxide of element 'Y'?
​

Answer 1

Required Answer :-

Given atomic number of "X" = 17.

• Configuration of "X" is 1s² 2s² 2p ⁵

Number of valence electrons of "X" are 2 + 5 which is equal to 7. So , "X" belongs to 7th group in periodic table. So , "X" is a non-metal. {∵Number of valence electrons = Group number}

Given atomic number of "Y" = 20

• Configuration of "Y" is 1s² 2s² 2p⁶ 3s²

Number of valence electrons of "Y" are 2. So , "Y" belongs to 2nd group in the periodic table. So , "Y" is an alkaline earth metal.

Now , When element "Y" forms oxide the nature of oxide will be basic in nature. Since , Metals forms basic oxides where as non-metals forms acidic oxides.

Answer 2

$\Large\bf{\color{cyan}GiVeN,}$

• Atomic no. of an element 'X' is 17.

• Atomic no. of another element 'Y' is 20.

$:\implies\:\:\bf\pink{X\:+\:Y\:\longrightarrow\:Compound\:}$

$\bf{\underline{\color{coral}Electronic\:configuration\:of\:X,}}$

$\longmapsto\:\:\bf{X\:\longrightarrow\:1s^2\:2s^2\:2p^6\:3s^2\:3p^5\:}$

☆ In K-shell 2 electrons are present.

☆ In L-shell 8 electrons are present.

☆ In M-shell 7 electrons are present.

Rules for find Group No. ;-

♨ If valency electrons of an element is 1 or 2, then the group no. is equal to no. of valency electrons (1 or 2).

♨ If valency electrons of an element are from 3-8, then the group no. is equal to (no. of valency electrons + 10).

✔ In this case valency electrons are 7. So group number of X is,

=》 10 + 7

=》 17

$\bf{\color{peru}Therefore,}$

Group no. of element X is 17 And name of the element is Chlorine.

$\bf{\underline{\color{coral}Electronic\:configuration\:of\:Y,}}$

$\longmapsto\:\:\bf{Y\:\longrightarrow\:1s^2\:2s^2\:2p^6\:3s^2\:3p^6\:4s^2\:}$

☆ In K-shell 2 electrons are present.

☆ In L-shell 8 electrons are present.

☆ In M-shell 8 electrons are present.

☆ In N-shell 2 electrons are present.

✔ In this case valency electrons are 2. So group number of Y is 2.

$\bf\blue{Therefore,}$

Group no. of element Y is 2 And name of the element is Calcium.

$\bf\red{We\:know\:that,}$

☆ When we move left to right of a period table metallic character was decreased.

☆ From starting (left side) first two groups elements are metallic in nature.

☆ And at end (right side) from group 13-17 almost elements are non-metallic in nature and some metalloids are also present.

$\bf\purple{Therefore,}$

X is Non-etal and Y is Metal.

♨ Y (Calcium) element is a metal. And we know that the tendency of a metal is to loss electrons easily.

♨ Hence the oxide formed by Y is calcium oxide (CaO). And we know that metal oxides are generally Basic in nature.

$\bf\green{Therefore,}$

The nature of oxide formed by element Y is Basic Oxide.