Respuesta :
Answer : The unknown element is, chlorine.
Explanation :
As we are given that there are seven valance electrons and two more protons than phosphorous.
As we know that, phosphorous is a non-metal which belongs to group 15.
The atomic number of phosphorous is, 15 that means there are 15 electrons in phosphorus atom.
The electronic configuration of phosphorus is:
[tex]1s^22s^22p^63s^23p^3[/tex]
As the unknown element has two more protons than phosphorus that is 15 + 2 = 17
The electronic configuration of will be:
[tex]1s^22s^22p^63s^23p^5[/tex]
The unknown element have seven valance electrons. Thus, the element will be chlorine.
Hence, the unknown element is, chlorine.
The unknown element is chlorine which has seven valence electrons.
Valence electrons:-
Given that there are seven valence electrons and two more protons than phosphorous.
Phosphorous is a non-metal which belongs to group 15. The atomic number of phosphorous is 15 which means there are 15 electrons in phosphorus atom.
The electronic configuration of phosphorus is:
[tex]1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{3}[/tex]
As the unknown element has two more protons than phosphorus that is 15 + 2 = 17
The electronic configuration now will be:
[tex]1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{5}[/tex]
The unknown element has seven valence electrons. Thus, the element will be chlorine.
Hence, the unknown element is chlorine.
Find out more information about the valence electrons here:-
brainly.com/question/371590
