Multiple Choice
Which of the following is the correct electron configuration for nobelium (No)?
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10. Periodic Properties of the Elements
The Electron Configuration
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Which of the following is the correct electron configuration for boron (atomic number 5)?
A
1s2 2s2 2p1
B
1s1 2s2 2p2
C
1s2 2s2 3s1
D
1s2 2s3
Verified step by step guidance1
Identify the atomic number of boron, which is 5. This means boron has 5 electrons to place in orbitals according to the Aufbau principle.
Recall the order of filling orbitals: 1s, 2s, 2p, 3s, etc. Each orbital can hold a specific maximum number of electrons: 1s and 2s can hold 2 electrons each, and 2p can hold up to 6 electrons.
Start filling the orbitals with electrons in order: first fill 1s with 2 electrons, then 2s with 2 electrons, and finally place the remaining 1 electron in the 2p orbital.
Write the electron configuration by indicating the number of electrons in each orbital: $1s^2 2s^2 2p^1$.
Compare this configuration with the given options to confirm that $1s^2 2s^2 2p^1$ correctly represents the electron configuration of boron.
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