JEE Main201912 Apr 2019Morning ShiftChemistryClassification of Elements and Periodicity in PropertiesActual
The group number, number of valence electrons, and valency of an element with atomic number 15 , respectively, are:
Options
- A15,6 and 2
- B16,6 and 3
- C16,5 and 2
- D15,5 and 3
Correct answer
D. 15,5 and 3
Step-by-step solution
Atomic number 15 electronic configuration is 15 → 1 s 2 , 2 s 2 , 2 p 6 , 3 s 2 , 3 p 3 and this element is Phosphorous. Group no = 15 Valence e - ⇒ e - present in valence shell = 2 + 3 = 5 Valency = 3 , it needs 3 electron to complete its octet.