Question

1. identify the following atoms as either paramagnetic or diamagnetic. (3)

(a) ga
(b) cr
(c) ni

Explanation:

To determine if an atom is paramagnetic or diamagnetic, we check the electron configuration for unpaired electrons. Paramagnetic atoms have unpaired electrons, while diamagnetic atoms have all electrons paired.

Part (a): Gallium (Ga)

1. Step 1: Determine the atomic number of Ga

The atomic number of Ga is 31.

1. Step 2: Write the electron configuration

The electron configuration of Ga is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^1\).

1. Step 3: Check for unpaired electrons

The \(4p\) orbital has 1 unpaired electron. Since there is an unpaired electron, Ga is paramagnetic.

Part (b): Chromium (Cr)

1. Step 1: Determine the atomic number of Cr

The atomic number of Cr is 24.

1. Step 2: Write the electron configuration

Chromium is an exception: its electron configuration is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5\) (instead of \(4s^2 3d^4\)) to achieve a half - filled \(d\) - orbital, which is more stable.

1. Step 3: Check for unpaired electrons

The \(4s\) orbital has 1 unpaired electron, and each of the five \(3d\) orbitals has 1 unpaired electron. With multiple unpaired electrons, Cr is paramagnetic.

Part (c): Nickel (Ni)

1. Step 1: Determine the atomic number of Ni

The atomic number of Ni is 28.

1. Step 2: Write the electron configuration

The electron configuration of Ni is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8\).

1. Step 3: Check for unpaired electrons

In the \(3d\) orbital (which can hold 10 electrons), 8 electrons are present. According to Hund's rule, the first 5 electrons fill the \(d\) - orbitals singly, and the remaining 3 electrons pair with 3 of the singly - occupied orbitals, leaving 2 unpaired electrons. Since there are unpaired electrons, Ni is paramagnetic.

Final Answers:

(a) \(\boldsymbol{\text{Paramagnetic}}\)
(b) \(\boldsymbol{\text{Paramagnetic}}\)
(c) \(\boldsymbol{\text{Paramagnetic}}\)

Answer:

To determine if an atom is paramagnetic or diamagnetic, we check the electron configuration for unpaired electrons. Paramagnetic atoms have unpaired electrons, while diamagnetic atoms have all electrons paired.

Part (a): Gallium (Ga)

1. Step 1: Determine the atomic number of Ga

The atomic number of Ga is 31.

1. Step 2: Write the electron configuration

The electron configuration of Ga is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^1\).

1. Step 3: Check for unpaired electrons

The \(4p\) orbital has 1 unpaired electron. Since there is an unpaired electron, Ga is paramagnetic.

Part (b): Chromium (Cr)

1. Step 1: Determine the atomic number of Cr

The atomic number of Cr is 24.

1. Step 2: Write the electron configuration

Chromium is an exception: its electron configuration is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5\) (instead of \(4s^2 3d^4\)) to achieve a half - filled \(d\) - orbital, which is more stable.

1. Step 3: Check for unpaired electrons

The \(4s\) orbital has 1 unpaired electron, and each of the five \(3d\) orbitals has 1 unpaired electron. With multiple unpaired electrons, Cr is paramagnetic.

Part (c): Nickel (Ni)

1. Step 1: Determine the atomic number of Ni

The atomic number of Ni is 28.

1. Step 2: Write the electron configuration

The electron configuration of Ni is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8\).

1. Step 3: Check for unpaired electrons

In the \(3d\) orbital (which can hold 10 electrons), 8 electrons are present. According to Hund's rule, the first 5 electrons fill the \(d\) - orbitals singly, and the remaining 3 electrons pair with 3 of the singly - occupied orbitals, leaving 2 unpaired electrons. Since there are unpaired electrons, Ni is paramagnetic.

Final Answers:

(a) \(\boldsymbol{\text{Paramagnetic}}\)
(b) \(\boldsymbol{\text{Paramagnetic}}\)
(c) \(\boldsymbol{\text{Paramagnetic}}\)