Chapter 1: Basic Concepts, Atomic Structure & Periodicity (Set-3)

The number of moles of H atoms present in 18 g of water is

A 0.5 mol

B 1.0 mol

C 2.0 mol

D 4.0 mol

The mass of 3.01 × 10²³ molecules of CO₂ is

A 11 g

B 22 g

C 44 g

D 88 g

If 4 g of H₂ reacts completely, the mass of oxygen required is

A 8 g

B 16 g

C 32 g

D 64 g

The volume occupied by 0.25 mol of any ideal gas at STP is

A 2.24 L

B 5.6 L

C 11.2 L

D 22.4 L

The percentage of carbon in CO₂ is closest to

A 12%

B 27%

C 44%

D 73%

In a compound, the mass ratio of elements is always fixed. This is

A Law of gaseous volumes

B Law of multiple proportions

C Law of constant proportions

D Avogadro’s law

The number of molecules in 18 g of glucose (C₆H₁₂O₆, molar mass 180) is

A 6.022×10226.022 \times 10^{22}6.022×1022

B 6.022×10216.022 \times 10^{21}6.022×1021

C 3.011×10223.011 \times 10^{22}3.011×1022

D 3.011×10233.011 \times 10^{23}3.011×1023

Which statement is correct for isotopes

A Same mass number, different atomic number

B Same atomic number, different mass number

C Same neutrons, different protons

D Same electrons only

The number of neutrons in 1735^{35}_{17}1735Cl is

A 17

B 18

C 35

D 52

The maximum number of electrons that can have n = 3 is

A 8

B 18

C 32

D 50

Total number of orbitals in a d-subshell is

A 3

B 5

C 7

D 9

Maximum number of electrons with l = 0 is

A 2

B 6

C 10

D 14

The angular momentum of an electron depends on

A n only

B l only

C m only

D s only

Which set of quantum numbers is not possible

A (n=3, l=2, m=0)

B (n=2, l=1, m=−1)

C (n=1, l=1, m=0)

D (n=4, l=0, m=0)

The electronic configuration of Fe (Z = 26) is

A [Ar] 4s² 3d⁶

B [Ar] 4s¹ 3d⁷

C [Ar] 4s² 3d⁵

D [Ar] 4s² 3d⁸

Which has anomalous electronic configuration

A Sc

B Cr

C Ti

D Zn

Effective nuclear charge across a period generally

A decreases

B remains constant

C increases

D becomes zero

Atomic size increases down a group mainly due to

A increase in nuclear charge only

B addition of new shells

C decrease in shielding

D increase in electronegativity

Which has the smallest ionic radius

A Na⁺

B Mg²⁺

C Al³⁺

D Cl⁻

Order of first ionization enthalpy is correctly represented by

A Na > Mg > Al > Si

B Si > Al > Mg > Na

C Mg > Na > Al > Si

D Al > Mg > Na > Si

Which has greater ionization enthalpy

A Al

B Mg

C Both equal

D Cannot be predicted

Electron affinity is least (almost zero) for

A Halogens

B Alkali metals

C Noble gases

D Chalcogens

Which element shows maximum non-metallic character in period 2

A Li

B C

C O

D F

Which one is strongest reducing agent in alkali metals

A Li

B Na

C K

D Cs

Which pair has the same number of neutrons

A 714N^{14}_7N714N and 815O^{15}_8O815O

B 816O^{16}_8O816O and 917F^{17}_9F917F

C 612C^{12}_6C612C and 714N^{14}_7N714N

D 919F^{19}_9F919F and 1020Ne^{20}_{10}Ne1020Ne

The number of moles of CO₂ produced when 5 moles of CH₄ burns completely is

A 2.5 mol

B 5 mol

C 10 mol

D 20 mol

In complete combustion, 16 g of CH₄ produces CO₂ mass equal to

A 22 g

B 44 g

C 88 g

D 11 g

The number of atoms in 1 mole of O₃ is

A 6.022×10236.022 \times 10^{23}6.022×1023

B 1.204×10241.204 \times 10^{24}1.204×1024

C 1.806×10241.806 \times 10^{24}1.806×1024

D 3.011×10233.011 \times 10^{23}3.011×1023

Which has the highest electronegativity

A Cl

B Br

C I

D F

Which is the correct decreasing order of atomic radius in group 17

A F > Cl > Br > I

B I > Br > Cl > F

C Cl > F > I > Br

D Br > I > Cl > F

Which element has the greatest tendency to gain one electron

A Na

B Mg

C Cl

D Ar

Which is the correct order of electron affinity (more negative to less negative)

A Cl > F > Br > I

B F > Cl > Br > I

C I > Br > Cl > F

D Br > Cl > F > I

The maximum number of electrons with n = 2 and l = 1 is

A 2

B 4

C 6

D 8

Total number of nodal planes in a p-orbital is

A 0

B 1

C 2

D 3

Which has the highest second ionization enthalpy

A Li

B Be

C Na

D Mg

Which is the correct statement about periodic trends

A Ionization enthalpy decreases across a period

B Atomic radius increases across a period

C Metallic character decreases across a period

D Electron affinity becomes zero for halogens

Which element has the greatest charge density in its cation

A Na⁺

B Mg²⁺

C Al³⁺

D K⁺

The most acidic oxide among the following is

A Na₂O

B MgO

C Al₂O₃

D SiO₂

Which element is a metalloid

A Na

B Mg

C Si

D S

If an element has configuration ns²np⁶, it belongs to

A Group 2

B Group 13

C Group 18

D Group 17

Which pair is correctly matched

A l=0 → p-subshell

B l=1 → p-subshell

C l=2 → p-subshell

D l=3 → d-subshell

Total number of electrons that can have m = 0 in a given shell is

A 1 only

B 2 only

C depends on number of orbitals with m=0

D always equals 6

The correct order of increasing ionic radius is

A Al³⁺ < Mg²⁺ < Na⁺

B Na⁺ < Mg²⁺ < Al³⁺

C Mg²⁺ < Na⁺ < Al³⁺

D Al³⁺ < Na⁺ < Mg²⁺

Which has the highest number of protons

A 2040Ca^{40}_{20}Ca2040Ca

B 1939K^{39}_{19}K1939K

C 1224Mg^{24}_{12}Mg1224Mg

D 1123Na^{23}_{11}Na1123Na

Which of the following shows maximum covalent character

A NaCl

B MgCl₂

C AlCl₃

D KCl

The correct order of increasing electronegativity in period 3 is

A Cl < S < P < Si

B Si < P < S < Cl

C P < Si < S < Cl

D S < P < Si < Cl

Which element has the highest electron affinity among these

A O

B S

C Cl

D Ne

Which statement is correct about atomic radius

A It decreases down the group

B It increases down the group

C It increases across a period

D It remains constant always

Which has the highest number of unpaired electrons in ground state

A C (Z=6)

B N (Z=7)

C O (Z=8)

D Ne (Z=10)

A substance contains 40% C, 6.67% H and 53.33% O by mass. The empirical formula is

A CH₂O

B C₂H₄O₂

C C₆H₁₂O₆

D CH₄O

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