An element with the electron configuration [noble gas] ns² (n - 1)d¹⁰ np³ belongs to the nitrogen group element - group 15 - in a period higher than 2. The element could be As, Sb or Bi. For example, arsenic (As) has the electron configuration [Ne] 4s² 3d¹⁰ 4p³.
The valence electrons are those in the highest energy level, in a s or p sublevel. For the elements with the general electron configuration [noble gas] ns² (n - 1)d¹⁰ np³ has 5 valence electrons: 2 electrons in a s sublevel and 3 electrons in a p sublevel. The electrons in the d orbital are in a lowest energy level (n-1).
To calculate percent errorsubtract the accepted value from the experimental value.Take the absolute value of step 1.Divide that answer by the accepted value.Multiply that answer by 100 so% error = [|(10.085 g/ 10 ml) - 0.9975| / 0.9975] x 100 % error = 1.1 %
