Class 11 – Classification of Elements and Periodicity in Properties (40 MCQs)
Early Attempts at Classification (1–5)
- Dobereiner’s triads were based on:
a) Atomic mass
b) Atomic number
c) Valency
d) Electronegativity - In Dobereiner’s triads, the atomic mass of the middle element is approximately:
a) Mean of other two
b) Sum of other two
c) Twice the lighter one
d) Half of heavier one - Newlands proposed:
a) Law of Triads
b) Law of Octaves
c) Modern Periodic Law
d) Atomic Number Law - Newlands’ Law of Octaves was criticized because:
a) Only worked for lighter elements
b) Did not consider noble gases
c) Grouping was irregular after calcium
d) All of the above - Mendeleev’s Periodic Table was arranged by:
a) Atomic number
b) Atomic mass
c) Valency only
d) Electronegativity
Modern Periodic Law & Periodic Table (6–11)
- Modern Periodic Law states that:
a) Properties repeat after 8 elements
b) Properties of elements are a periodic function of atomic number
c) Elements arranged by atomic mass
d) None of the above - Which is a major advantage of the modern periodic table over Mendeleev’s?
a) Prediction of new elements
b) Grouping by atomic number avoids irregularities
c) No need for triads
d) Both a & b - Periods in the modern periodic table correspond to:
a) Number of valence electrons
b) Number of electron shells
c) Atomic mass
d) Number of protons - Groups in the modern periodic table correspond to:
a) Number of electron shells
b) Number of valence electrons
c) Atomic number
d) Mass number - The s-block elements include:
a) Groups 1 and 2
b) Groups 13–18
c) Transition metals
d) Lanthanides - The p-block elements include:
a) Groups 13–18
b) Groups 1–2
c) Transition metals
d) Actinides
Periodic Trends: Atomic & Ionic Radius (12–16)
- Atomic radius generally:
a) Increases across a period
b) Decreases across a period
c) Remains constant across a period
d) Increases across a group - Atomic radius generally:
a) Increases down a group
b) Decreases down a group
c) Remains constant down a group
d) Fluctuates randomly - Cationic radius is:
a) Larger than neutral atom
b) Smaller than neutral atom
c) Equal to neutral atom
d) Same as anion - Anionic radius is:
a) Smaller than neutral atom
b) Larger than neutral atom
c) Equal to neutral atom
d) Same as cation - Which of the following has the smallest atomic radius?
a) Li
b) Be
c) B
d) F
Ionization Energy & Electron Affinity (17–21)
- Ionization energy generally:
a) Increases across a period
b) Decreases across a period
c) Remains constant
d) Increases down a group - Ionization energy generally:
a) Decreases down a group
b) Increases down a group
c) Remains constant
d) Random - Electron affinity is:
a) Energy released when an electron is added to neutral atom
b) Energy required to remove electron
c) Energy of proton
d) Mass of electron - Which element has the highest ionization energy in period 2?
a) Li
b) C
c) N
d) F - Which element has the most negative electron affinity?
a) Li
b) O
c) F
d) Ne
Electronegativity & Valency (22–25)
- Electronegativity generally:
a) Increases across a period
b) Decreases across a period
c) Remains constant
d) Random - Electronegativity generally:
a) Decreases down a group
b) Increases down a group
c) Remains constant
d) Fluctuates - Valency of an element is determined by:
a) Number of electron shells
b) Number of valence electrons
c) Atomic mass
d) Ionization energy - Which element has highest electronegativity in periodic table?
a) Oxygen
b) Fluorine
c) Nitrogen
d) Chlorine
Chemical Reactivity & Periodicity (26–30)
- Alkali metals react with water to produce:
a) Acid + H₂
b) Base + H₂
c) Salt only
d) Neutral solution - Among halogens, reactivity:
a) Increases down the group
b) Decreases down the group
c) Remains same
d) Random - Which is more reactive: Na or K?
a) Na
b) K
c) Both same
d) Cannot say - Which noble gas is chemically inert?
a) Ne
b) He
c) Ar
d) All of these - Which element shows anomalous behavior in group 13?
a) B
b) Al
c) Ga
d) Tl
Transition Elements & Miscellaneous (31–40)
- Transition elements are in:
a) d-block
b) s-block
c) p-block
d) f-block - Transition metals show:
a) Variable oxidation states
b) Formation of colored compounds
c) Catalytic properties
d) All of the above - Lanthanides are called:
a) Inner transition metals
b) Noble metals
c) Alkali metals
d) Halogens - Actinides are mostly:
a) Radioactive
b) Non-radioactive
c) Noble gases
d) Alkaline earth metals - Group 18 elements are called:
a) Halogens
b) Noble gases
c) Alkali metals
d) Alkaline earth metals - Periodicity in chemical properties is due to:
a) Atomic mass
b) Atomic number
c) Valence electrons
d) Both b & c - Which is the most electropositive element?
a) Li
b) Cs
c) Na
d) K - Which has the highest first ionization energy?
a) Li
b) F
c) Ne
d) Be - Which has largest atomic radius in period 3?
a) Na
b) Mg
c) Al
d) Cl - Which element has highest metallic character?
a) Na
b) Mg
c) Al
d) Si
Answer Key – Class 11 Chemistry: Classification of Elements and Periodicity in Properties (40 MCQs)
Early Attempts at Classification (1–5)
- a) Atomic mass – Dobereiner’s triads were based on average atomic mass.
- a) Mean of other two – Middle element ≈ average of lighter and heavier element.
- b) Law of Octaves – Newlands’ periodicity law.
- d) All of the above – Criticized for irregular grouping after calcium, noble gases not included.
- b) Atomic mass – Mendeleev arranged elements by increasing atomic mass.
Modern Periodic Law & Periodic Table (6–11)
- b) Properties of elements are a periodic function of atomic number – Modern periodic law.
- d) Both a & b – Modern table fixed irregularities and allowed prediction of new elements.
- b) Number of electron shells – Period corresponds to principal quantum number.
- b) Number of valence electrons – Determines chemical properties.
- a) Groups 1 and 2 – s-block elements.
- a) Groups 13–18 – p-block elements.
Periodic Trends: Atomic & Ionic Radius (12–16)
- b) Decreases across a period – Increasing nuclear charge pulls electrons closer.
- a) Increases down a group – New shells added, radius increases.
- b) Smaller than neutral atom – Cations lose electrons → smaller radius.
- b) Larger than neutral atom – Anions gain electrons → larger radius.
- d) F – Fluorine has highest nuclear charge, smallest radius.
Ionization Energy & Electron Affinity (17–21)
- a) Increases across a period – Stronger nuclear attraction.
- a) Decreases down a group – Electrons farther from nucleus.
- a) Energy released when an electron is added to neutral atom – Definition of electron affinity.
- d) F – Highest ionization energy in period 2.
- c) F – Most negative electron affinity.
Electronegativity & Valency (22–25)
- a) Increases across a period – Nuclear charge increases, electrons more strongly attracted.
- a) Decreases down a group – Electrons farther from nucleus.
- b) Number of valence electrons – Valency is based on valence electrons.
- b) Fluorine – Highest electronegativity.
Chemical Reactivity & Periodicity (26–30)
- b) Base + H₂ – Alkali metals react with water to produce hydroxides and hydrogen gas.
- b) Decreases down the group – Halogen reactivity decreases down the group.
- b) K – More reactive than Na due to lower ionization energy.
- d) All of these – Noble gases are chemically inert.
- a) B – Boron shows anomalous behavior due to small size and high electronegativity.
Transition Elements & Miscellaneous (31–40)
- a) d-block – Transition elements occupy d-orbitals.
- d) All of the above – Variable oxidation states, colored compounds, catalysts.
- a) Inner transition metals – Lanthanides are f-block elements.
- a) Radioactive – Most actinides are radioactive.
- b) Noble gases – Group 18 elements.
- d) Both b & c – Periodicity arises from atomic number and valence electrons.
- b) Cs – Most electropositive element.
- c) Ne – Highest first ionization energy.
- a) Na – Largest atomic radius in period 3.
- a) Na – Highest metallic character in period 3.
Disclaimer:
All MCQs on this page are created for educational purposes only. They are intended for practice and NEET/Class 11 Chemistry preparation and do not guarantee any specific exam results.