Consider the following figure which represents an element block on the periodic table. If this is the block for the nonmetal found in period 3 group 5A,the question marks 1,2,and 3 should be filled in,respectively,with which of the following?

Question

Consider the following figure which represents an element block on the periodic table.  If this is the block for the nonmetal found in period 3 group 5A,the question marks 1,2,and 3 should be filled in,respectively,with which of the following?

Quizplus · Accepted Answer

The nonmetal in period 3 group 5A is nitrogen (N). The element block shows the electron configuration of the element with the highest energy level in that group, which is phosphorus (P). 
1. The question mark under the symbol represents the atomic number, which is the number of protons in the nucleus. The atomic number of phosphorus is 15, so the answer is C.
2. The question mark under the electron configuration represents the shorthand notation for the arrangement of electrons in the energy levels. The electron configuration of phosphorus is [Ne] 3s2 3p3, so the answer is P.
3. The question mark under the atomic mass represents the weighted average of the masses of all the isotopes of the element. The atomic mass of phosphorus is 30.97, so the answer is also P.

Consider the Following Figure Which Represents an Element Block on the Periodic