How many energy levels contain electrons in an atom of zirconium (Zr)?The Periodic TableA.NineB.TwoC.FourD.FiveSUBMITarrow_backPREVIOUS

1. Break Down the Problem

To determine how many energy levels contain electrons in an atom of zirconium (Zr), we first need to identify its atomic number and electronic configuration. The atomic number of zirconium is 40, meaning it has 40 electrons.

2. Relevant Concepts

The electrons are arranged in energy levels (or shells) around the nucleus of the atom. The electrons fill these energy levels according to the Aufbau principle, and the maximum number of electrons in each energy level can be calculated using the formula $2n^2$, where $n$ is the principle quantum number (energy level).

3. Analysis and Detail

1. Zr has an atomic number of 40, so it has 40 electrons.

2. The electron configuration of zirconium is:

   • 1st level: $2$ electrons
   • 2nd level: $8$ electrons
   • 3rd level: $18$ electrons
   • 4th level: $12$ electrons

   This filling can be summarized as:

   • Level 1: 2
   • Level 2: 8
   • Level 3: 18
   • Level 4: 12

   In total:

   • 1 + 2 + 3 + 4 = 4 energy levels are fully filled containing electrons.

4. Verify and Summarize

Thus, the four energy levels that can contain electrons in zirconium are filled as allowed up to the atomic number 40. The fourth level has electrons, thereby confirming that there are four energy levels occupied.

Final Answer

The number of energy levels containing electrons in an atom of zirconium (Zr) is Four (C).