60 public questions tagged with this topic.
Group 17 elements (halogens) have 7 valence electrons, with outer configuration ns² np⁵.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Nomenclature of Elements with Atomic Number >100
In group 16, O₂ is a linear diatomic gas at room temperature, unlike SO₂ (bent), SeO₂ (polymeric solid), or TeO₂ (solid).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Nomenclature of Elements with Atomic Number >100
Si (group 14, valence 4) and Cl (group 17, valence 1) form SiCl₄, a covalent compound, by sharing electrons to complete octets.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Nomenclature of Elements with Atomic Number >100
Atomic radius decreases across a period and increases down a group. Among F, Cl, Br, and I (group 17), Iodine (I), being lowest in the group, has the largest atomic radius.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Nomenclature of Elements with Atomic Number >100
For isoelectronic species (10 electrons), effective nuclear charge increases with atomic number. Al³⁺ (Z=13) has the highest effective nuclear charge compared to Na+, Mg²⁺, or F⁻.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Nomenclature of Elements with Atomic Number >100
Molecular diagnostics uses advanced techniques like PCR and DNA probes, not just microscopic_x000D_ observations, for accurate detection of diseases and genetic mutations.
Ref: NCERT Class 12 Biology Chapter 10: Biotechnology and its Applications Medical Applications - Molecular Diagnosis - PCR ELISA
Molecular diagnostics uses advanced techniques like PCR, DNA probes, and sequencing, not just visual_x000D_ inspection, for accurate detection.
Ref: NCERT Class 12 Biology Chapter 10: Biotechnology and its Applications Medical Applications - Molecular Diagnosis - PCR ELISA
Bacillus thuringiensis (Bt) toxin is specific to insect larvae and does not affect human intestinal cells.
Ref: NCERT Class 12 Biology Chapter 8: Microbes in Human Welfare Microbes as Biocontrol Agents - Bt Baculovirus Trichoderma
Passive immunity is acquired when ready-made antibodies are transferred from another source, such as maternal antibodies or antibody injections.
Ref: NCERT Class 12 Biology Chapter 7: Human Health and Disease Immunity - Acquired Immunity - Active Passive Vaccination
Vaccines do not provide immediate immunity; they take time to generate an immune response and develop memory cells.
Ref: NCERT Class 12 Biology Chapter 7: Human Health and Disease Immunity - Acquired Immunity - Active Passive Vaccination
Vaccines do not provide immediate immunity; they take time to generate an immune response and develop memory cells.
Ref: NCERT Class 12 Biology Chapter 7: Human Health and Disease Immunity - Acquired Immunity - Active Passive Vaccination
Vaccines provide **active** immunity by stimulating the immune system, not passive immunity.
Ref: NCERT Class 12 Biology Chapter 7: Human Health and Disease Immunity - Acquired Immunity - Active Passive Vaccination
