Predict the valency of the following along with the name of the element:
a) Z= 19
b) Z= 15
c) Z= 7
d) Z=12
please help
Answers
Required Answer :-
a) Z = 19
Element with Atomic number 19 is Potassium. Number of electrons is equal to Atomic number (only when it is neutral) . So , Number of electrons are 19. Now , the Electronic configuration is , 1s² 2s² 2p⁶ 3s² 3p⁶4s¹. Electrons present in the outermost shell are called valence electrons. Observing the configuration , number of electrons present in outermost shell is 1. So , Valency of Potassium is 1.
b) Z = 15
Element with atomic number 15 is Phosphorus. Number of electrons is equal to Atomic number (only when it is neutral) . So , Number of electrons are 15. Now , the Electronic configuration is , 1s² 2s² 2p⁶ 3s² 3p³. Observing the configuration , Number of electrons present in outermost shell is 2+3 = 5 . So , Valency of potassium is 5.
c) Z = 7
Element with atomic number 7 is nitrogen . Number of electrons is equal to Atomic number (only when it is neutral) . So , Number of electrons are 7. Now , the Electronic configuration is , 1s² 2s² 2p³. Observing the electronic configuration , number of electrons present in outermost shell is 2+3 = 5 . So , Valency of nitrogen is 5.
d) Z = 12
Element with atomic number 12 is Magnesium . Number of electrons is equal to Atomic number (only when it is neutral) . So , Number of electrons are 19. Now , the Electronic configuration is , 1s² 2s² 2p⁶ 3s². Observing the configuration , number of electrons present in outermost shell is 2. So , Valency of magnesium is 2.