Chemistry MCQs
Topic Notes: Chemistry
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
21
How does the atomic radius of potassium compare to that of sodium?
Answer:
more than
Atomic radius generally increases down a group in the periodic table. Since potassium (K) is located in the fourth period and sodium (Na) is in the third period, potassium has an additional electron shell, resulting in a larger atomic radius.
22
Which of the following atoms has the smallest atomic volume?
Answer:
He
Atomic volume generally decreases across a period due to increasing effective nuclear charge pulling electrons closer. Helium (He) is in the first period and has the smallest principal quantum number (n=1), resulting in a significantly smaller atomic radius and volume compared to P, S, and Si in the third period.
23
What electronegativity difference between atoms indicates the formation of an ionic bond?
Answer:
Greater than 1.7
Ionic bonds form when there's a significant electronegativity difference between atoms. A difference greater than 1.7 indicates a large disparity in electron-attracting ability, leading to electron transfer and the formation of ions.
24
What is the typical characteristic of ionic crystals?
Answer:
Compound forming
Ionic crystals typically exhibit compound forming properties due to the electrostatic attraction between positively and negatively charged ions, resulting in the formation of a stable crystal lattice.
25
Which of the following mineral salts is most soluble in water?
Answer:
MgSO4
The solubility of mineral salts in water depends on their ionic sizes and the nature of the ions. Among the given options, MgSO4 (Epsom salt) has smaller ions, which allows it to dissolve more easily in water, making it the most soluble mineral salt in water.
26
Which one shows high %age of the ionic character ?
Answer:
HF
Manual review recommended: automated enrichment was incomplete for this item. The original answer and options were preserved. No Gemini key is configured. Add GEMINI_API_KEY to the local server environment or save a Gemini provider key in Settings.
27
In an ionic bond, what is completely transferred to form the bond?
Answer:
Electrons
An ionic bond is formed when one atom completely transfers its electrons to another atom, resulting in the formation of ions with opposite charges. This transfer of electrons is essential for the formation of an ionic bond, which holds the atoms together.
28
What type of crystal structure do carbon dioxide (CO2) molecules form in dry ice?
Answer:
Molecular crystal
Dry ice is solid carbon dioxide. CO2 molecules are held together by weak intermolecular forces, leading to a molecular crystal structure. This is unlike ionic or covalent crystals, which involve strong electrostatic or covalent bonds between atoms.
29
What type of crystal lattice structure does table salt adopt?
Answer:
Body centered cubic lattice
Table salt (NaCl) forms a body-centered cubic (BCC) lattice. In this structure, sodium (Na+) ions occupy the corners of the cube, while chloride (Cl-) ions occupy the center of each cube. This arrangement maximizes ionic interactions and results in a stable crystal structure.