Question

electrons and the periodic table
quiz complete
1 2 3 4 5 6 7 8 9 10
which is the electron configuration for nobelium (no)?
○ rn7s²5f¹⁴
○ rn7s²5f⁷
○ ne3s²3p⁷
○ xe6s²5d¹

Explanation:

2.

Step2: Find nearest noble gas core

Radon (Rn, atomic number 86) is the preceding noble gas, so we use [Rn] as the core.

Step3: Calculate remaining electrons

$102 - 86 = 16$ electrons left to fill.

Step4: Fill valence orbitals in order

First fill 7s orbital: $7s^2$ (2 electrons used, 14 left).
Then fill 5f orbital: $5f^{14}$ (14 electrons used, 0 left).

Step5: Combine core and valence orbitals

Electron configuration: $[Rn]7s^25f^{14}$

Answer:

2.

Step2: Find nearest noble gas core

Radon (Rn, atomic number 86) is the preceding noble gas, so we use [Rn] as the core.

Step3: Calculate remaining electrons

$102 - 86 = 16$ electrons left to fill.

Step4: Fill valence orbitals in order

First fill 7s orbital: $7s^2$ (2 electrons used, 14 left).
Then fill 5f orbital: $5f^{14}$ (14 electrons used, 0 left).

Step5: Combine core and valence orbitals

Electron configuration: $[Rn]7s^25f^{14}$