Question

write the full electron configuration and draw the orbital notation for each of the following atoms: 1. boron 2. helium 3. sulfur 4. argon 5. *for each subshell below, indicate the maximum number of electrons that can be found. 1s: __ 2s: 2p: 3s: 3p: __ 6. explain how the quantum mechanical model differs from the bohr model.

Explanation:

Step1: Recall electron - filling rules

Electrons fill orbitals in order of increasing energy (1s < 2s < 2p < 3s < 3p etc.). The s - subshell has 1 orbital and can hold 2 electrons, and the p - subshell has 3 orbitals and can hold 6 electrons.

Step2: Determine electron configuration of Boron

Boron has 5 electrons. The electron configuration is $1s^{2}2s^{2}2p^{1}$. For orbital notation, the 1s orbital has 2 paired electrons (arrows in opposite directions), the 2s orbital has 2 paired electrons, and the 2p orbital has 1 unpaired electron.

Step3: Determine electron configuration of Helium

Helium has 2 electrons. The electron configuration is $1s^{2}$. In orbital notation, the 1s orbital has 2 paired electrons.

Step4: Determine electron configuration of Sulfur

Sulfur has 16 electrons. The electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$. In orbital notation, 1s has 2 paired electrons, 2s has 2 paired electrons, 2p has 6 paired electrons (3 pairs), 3s has 2 paired electrons, and 3p has 4 electrons with 2 unpaired (following Hund's rule).

Step5: Determine electron configuration of Argon

Argon has 18 electrons. The electron configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$. In orbital notation, 1s has 2 paired electrons, 2s has 2 paired electrons, 2p has 6 paired electrons, 3s has 2 paired electrons, and 3p has 6 paired electrons.

Step6: Find maximum number of electrons in sub - shells

1s: 2 (since s - subshell has 1 orbital and each orbital can hold 2 electrons), 2s: 2, 2p: 6 (p - subshell has 3 orbitals and 3×2 = 6), 3s: 2, 3p: 6.

Step7: Compare quantum mechanical and Bohr models

The Bohr model depicts electrons in fixed circular orbits around the nucleus. The quantum mechanical model describes electrons in terms of probability distributions (orbitals) around the nucleus. The quantum mechanical model also takes into account the wave - like nature of electrons and provides a more accurate description of electron behavior.

Answer:

1. Boron electron configuration: $1s^{2}2s^{2}2p^{1}$; Orbital notation: 1s (↑↓), 2s (↑↓), 2p (↑)
2. Helium electron configuration: $1s^{2}$; Orbital notation: 1s (↑↓)
3. Sulfur electron configuration: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$; Orbital notation: 1s (↑↓), 2s (↑↓), 2p (↑↓)(↑↓)(↑↓), 3s (↑↓), 3p (↑↓)(↑)(↑)
4. Argon electron configuration: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$; Orbital notation: 1s (↑↓), 2s (↑↓), 2p (↑↓)(↑↓)(↑↓), 3s (↑↓), 3p (↑↓)(↑↓)(↑↓)
5. 1s: 2, 2s: 2, 2p: 6, 3s: 2, 3p: 6
6. The Bohr model has electrons in fixed circular orbits; the quantum mechanical model describes electrons in terms of probability distributions (orbitals) and accounts for the wave - like nature of electrons.