Question

Elements A,BC,D and E having atomic number 4,9,14,19,20 name the elements having same valence electrons​

Answer 1

Answer:

The elements A and E have the same numbers of valence electrons, i.e., $2$.

Explanation:

Given,

The atomic number of element A = $4$

The atomic number of element B = $9$

The atomic number of element C = $14$

The atomic number of element D = $19$

The atomic number of element E = $20$

The elements having the same valence electrons are =?

1) Element A ( Z = $4$ )

• The electronic configuration = $1s^{2}2s^{2}$
• The valence shell is $2s$

Therefore, the valence electrons are = $2$.

2) Element B ( Z = $9$ )

• The electronic configuration = $1s^{2}2s^{2}2p^{5}$
• The valence shells are $2s$ and $2p$

Therefore, the valence electrons are = $7$.

3) Element C ( Z = $14$ )

• The electronic configuration = $1s^{2}2s^{2}2p^{6}3s^{2}3p^{2}$
• The valence shells are $3s$ and $3p$

Therefore, the valence electrons are = $4$.

4) Element D ( Z = $19$ )

• The electronic configuration = $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}$
• The valence shell is $4s$

Therefore, the valence electron is = $1$.

5) Element E ( Z = $20$ )

• The electronic configuration = $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}$
• The valence shell is $4s$

Therefore, the valence electrons are = $2$.

Hence, the elements A and E have the same numbers of valence electrons, i.e., $2$.

Answer 2

Answer:

This is the required answer.

Explanation:

As per the data given in the question we have to find name the elements having same valence electrons​.

As per the question it is given that Elements A,BC,D and E having atomic number 4,9,14,19,20 .

According to question atomic number of element A =4

Atomic number of element B =9

Atomic number of element C = 14

Atomic number of element D = 19

Atomic number of element E = 20

1) Element A ( Z =4  )

Beryllium of atomic no -4 and

electronic configuration =[He]$2s^{2}$

The valence electrons are = 2 and it is in S block .

2) Element B ( Z =9 )

Fluorine of atomic no -9 and

electronic configuration =[He]$2s^{2}$ $2p^{5}$

The valence electrons are = 1 and it is in p block .

3) Element C ( Z =14  )

Silicon of atomic no -14 and

electronic configuration =[Ne]$3s^{2}$ $3p^{2}$

The valence electrons are = 4 and it is in p block .

4) Element D ( Z =19 )

Potassium of atomic no -19 and

electronic configuration =[Ar]$4s^{1}$

The valence electrons are = 1 and it is in s block .

5) Element E ( Z =20 )

Calcium of atomic no -20 and

electronic configuration =[Ar]$4s^{2}$

The valence electrons are = 2 and it is in s block .

Hence, this is the required answer.

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