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What are Paramagnetic Substances (Solid State)?
Grade Level:
Class 12
AI/ML, Physics, Biotechnology, FinTech, EVs, Space Technology, Climate Science, Blockchain, Medicine, Engineering, Law, Economics
Definition
What is it?
Paramagnetic substances are materials that are weakly attracted to an external magnetic field. This happens because they have unpaired electrons, which act like tiny magnets that can align with the external field.
Simple Example
Quick Example
Imagine you have a stack of school notebooks, and some of them have a single, loose magnet stuck inside (unpaired electrons). When you bring a big magnet (external magnetic field) near the stack, only the notebooks with the loose magnets will slightly turn and get pulled towards the big magnet. The other notebooks without loose magnets won't react much.
Worked Example
Step-by-Step
Let's figure out if a substance like Oxygen (O2) is paramagnetic.
Step 1: Find the electron configuration for an Oxygen atom. Oxygen has 8 electrons, so its configuration is 1s2 2s2 2p4.
---Step 2: Consider the molecular orbital theory for O2. When two oxygen atoms combine, their atomic orbitals merge to form molecular orbitals.
---Step 3: Fill the molecular orbitals with the total number of valence electrons (6 from each O atom = 12 valence electrons for O2).
---Step 4: The molecular orbital diagram for O2 shows two unpaired electrons in the anti-bonding pi orbitals (π*2px and π*2py).
---Step 5: Since O2 has unpaired electrons, it is weakly attracted to a magnetic field.
---Answer: Yes, Oxygen (O2) is a paramagnetic substance.
Why It Matters
Understanding paramagnetism helps engineers design better MRI machines for medicine and develop new catalysts for chemical reactions. It's also crucial in materials science for creating advanced magnets used in EVs and renewable energy technologies.
Common Mistakes
MISTAKE: Confusing paramagnetic with diamagnetic substances. | CORRECTION: Paramagnetic substances are *attracted* to a magnetic field due to *unpaired* electrons, while diamagnetic substances are *repelled* due to *all paired* electrons.
MISTAKE: Thinking that all substances with electrons are paramagnetic. | CORRECTION: Only substances with *unpaired* electrons in their atomic or molecular orbitals are paramagnetic. If all electrons are paired, it's diamagnetic.
MISTAKE: Believing paramagnetism is a very strong attraction. | CORRECTION: Paramagnetism is a *weak* attraction to a magnetic field. Strong attraction is characteristic of ferromagnetic substances.
Practice Questions
Try It Yourself
QUESTION: Is a substance with 5 unpaired electrons paramagnetic or diamagnetic? | ANSWER: Paramagnetic
QUESTION: Iron (Fe) has a d-block electron configuration. Can it be paramagnetic? Explain briefly. | ANSWER: Yes, Iron can be paramagnetic because transition metals like Iron often have unpaired electrons in their d-orbitals.
QUESTION: If a compound contains a metal ion with a d4 configuration and forms a high-spin complex, how many unpaired electrons would it have, and would it be paramagnetic? | ANSWER: In a high-spin d4 complex, there would be 4 unpaired electrons. Yes, it would be paramagnetic.
MCQ
Quick Quiz
Which of the following describes a paramagnetic substance?
Weakly repelled by an external magnetic field
Strongly attracted by an external magnetic field
Weakly attracted by an external magnetic field
Unaffected by an external magnetic field
The Correct Answer Is:
C
Paramagnetic substances are characterized by their weak attraction to an external magnetic field due to the presence of unpaired electrons. Options A and D describe diamagnetic substances or non-magnetic substances, while B describes ferromagnetic substances.
Real World Connection
In the Real World
In an MRI (Magnetic Resonance Imaging) scan, doctors use strong magnetic fields to create detailed images inside your body. The water molecules in your body, though diamagnetic, interact with paramagnetic contrast agents (like gadolinium compounds) sometimes injected to highlight specific tissues, helping diagnose illnesses like cancer or brain disorders.
Key Vocabulary
Key Terms
UNPAIRED ELECTRONS: Electrons that occupy an orbital alone, without a partner electron. | MAGNETIC FIELD: An area around a magnet where magnetic force can be felt. | MOLECULAR ORBITAL THEORY: A theory that describes how atomic orbitals combine to form molecular orbitals in a molecule. | DIAMAGNETIC: Substances that are weakly repelled by a magnetic field, having all paired electrons.
What's Next
What to Learn Next
Next, you should explore 'Diamagnetic Substances' to understand the opposite behavior and 'Ferromagnetic Substances' to learn about very strong magnetic materials. This will give you a complete picture of how different materials interact with magnets.
