Question

electronic configurations:
directions: for each element or ion give the full electron configuration, the abbreviated configuration, the diagram configuration and the 4 quantum numbers based on the last electron.

na⁺

whole: 1s²2s²2p⁶3s¹

abbreviated: ne(1s²2s²2p⁶)

diagram: orbital diagrams for 1s, 2s, 2p, 3p

n = 2

l = 1
mₗ = +1
mₛ = blank |

cl⁻

whole: blank

abbreviated: ar blank

diagram: blank

n blank

l blank
mₗ blank
mₛ blank |

cr

whole: blank

abbreviated: blank

diagram: blank

n blank

l blank
mₗ blank
mₛ blank |

Answer:

For $\boldsymbol{\ce{Na+}}$ (First, correct the initial mistakes in the given work):

Full Electron Configuration:

Sodium atom ($\ce{Na}$) has 11 electrons, $\ce{Na+}$ loses 1 electron, so it has 10 electrons.
The full electron configuration is $1s^2 2s^2 2p^6$.

Abbreviated (Noble Gas) Configuration:

The nearest noble gas with less electrons than $\ce{Na+}$ is Neon ($\ce{Ne}$) with electron configuration $1s^2 2s^2 2p^6$. So abbreviated configuration is $[\ce{Ne}]$.

Orbital Diagram (Diagram Configuration):

• $1s$: $\boldsymbol{\uparrow \downarrow}$
• $2s$: $\boldsymbol{\uparrow \downarrow}$
• $2p$: $\boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow}$
• $3s$: (empty, since $\ce{Na+}$ has lost the $3s^1$ electron)

Quantum Numbers for the Last Electron (Note: For $\ce{Na+}$, the last electron is in the $2p$ subshell. Let's take one of the $2p$ electrons):

• Principal quantum number ($n$): For $2p$, $n = 2$.
• Azimuthal quantum number ($l$): For $p$ subshell, $l = 1$ (since $l = 0$ for $s$, $l = 1$ for $p$, $l = 2$ for $d$, etc.).
• Magnetic quantum number ($m_l$): Can be $-1, 0, +1$ (for $l = 1$, $m_l$ ranges from $-l$ to $+l$). Let's take $m_l = +1$ (or any of the valid values).
• Spin quantum number ($m_s$): Can be $+\frac{1}{2}$ or $-\frac{1}{2}$. Let's take $m_s = +\frac{1}{2}$.

For $\boldsymbol{\ce{Cl-}}$:

Chlorine atom ($\ce{Cl}$) has 17 electrons, $\ce{Cl-}$ gains 1 electron, so it has 18 electrons.

Full Electron Configuration:

$1s^2 2s^2 2p^6 3s^2 3p^6$

Abbreviated (Noble Gas) Configuration:

The nearest noble gas with 18 electrons is Argon ($\ce{Ar}$) with electron configuration $1s^2 2s^2 2p^6 3s^2 3p^6$. So abbreviated configuration is $[\ce{Ar}]$.

Orbital Diagram (Diagram Configuration):

• $1s$: $\boldsymbol{\uparrow \downarrow}$
• $2s$: $\boldsymbol{\uparrow \downarrow}$
• $2p$: $\boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow}$
• $3s$: $\boldsymbol{\uparrow \downarrow}$
• $3p$: $\boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow}$

Quantum Numbers for the Last Electron (Last electron is in $3p$ subshell):

• $n$: For $3p$, $n = 3$.
• $l$: For $p$ subshell, $l = 1$.
• $m_l$: Can be $-1, 0, +1$ (e.g., $m_l = +1$).
• $m_s$: $+\frac{1}{2}$ (or $-\frac{1}{2}$).

For $\boldsymbol{\ce{Cr}}$ (Chromium, atomic number 24):

Chromium has an exception in electron configuration (follows $3d^5 4s^1$ instead of $3d^4 4s^2$ for stability, as half-filled $d$ subshell is more stable).

Full Electron Configuration:

$1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1$

Abbreviated (Noble Gas) Configuration:

Nearest noble gas below Cr is Argon ($\ce{Ar}$) with $1s^2 2s^2 2p^6 3s^2 3p^6$. So abbreviated configuration is $[\ce{Ar}] 3d^5 4s^1$.

Orbital Diagram (Diagram Configuration):

• $1s$: $\boldsymbol{\uparrow \downarrow}$
• $2s$: $\boldsymbol{\uparrow \downarrow}$
• $2p$: $\boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow}$
• $3s$: $\boldsymbol{\uparrow \downarrow}$
• $3p$: $\boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow} \ \boldsymbol{\uparrow \downarrow}$
• $3d$: $\boldsymbol{\uparrow} \ \boldsymbol{\uparrow} \ \boldsymbol{\uparrow} \ \boldsymbol{\uparrow} \ \boldsymbol{\uparrow}$ (half - filled, 5 electrons, each in separate orbitals with parallel spin)
• $4s$: $\boldsymbol{\uparrow}$

Quantum Numbers for the Last Electron (Last electron is in $4s^1$):

• $n$: For $4s$, $n = 4$.
• $l$: For $s$ subshell, $l = 0$.
• $m_l$: For $l = 0$, $m_l = 0$.
• $m_s$: $+\frac{1}{2}$ (or $-\frac{1}{2}$; since it's a single electron in $4s$, spin can be either, but typically taken as $+\frac{1}{2}$ for the first electron in a subshell).

Filling the Table (Corrected for $\boldsymbol{\ce{Na+}}$, and completed for $\boldsymbol{\ce{Cl-}}$, $\boldsymbol{\ce{Cr}}$):

Species	Whole Electron Configuration	Abbreviated Configuration	Diagram Configuration (Orbital Diagram)	Quantum Numbers (Last Electron) <br> $n, l, m_l, m_s$
$\ce{Cl-}$	$1s^2 2s^2 2p^6 3s^2 3p^6$	$[\ce{Ar}]$	$1s: \uparrow \downarrow$ <br> $2s: \uparrow \downarrow$ <br> $2p: \uparrow \downarrow \ \uparrow \downarrow \ \uparrow \downarrow$ <br> $3s: \uparrow \downarrow$ <br> $3p: \uparrow \downarrow \ \uparrow \downarrow \ \uparrow \downarrow$	$n = 3, \ l = 1, \ m_l = +1, \ m_s = +\frac{1}{2}$ (or other valid $m_l, m_s$)
$\ce{Cr}$	$1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1$	$[\ce{Ar}] 3d^5 4s^1$	$1s: \uparrow \downarrow$ <br> $2s: \uparrow \downarrow$ <br> $2p: \uparrow \downarrow \ \uparrow \downarrow \ \uparrow \downarrow$ <br> $3s: \uparrow \downarrow$ <br> $3p: \uparrow \downarrow \ \uparrow \downarrow \ \uparrow \downarrow$ <br> $3d: \uparrow \ \uparrow \ \uparrow \ \uparrow \ \uparrow$ <br> $4s: \uparrow$	$n = 4, \ l = 0, \ m_l = 0, \ m_s = +\frac{1}{2}$ (or $-\frac{1}{2}$)