Which noble gas has the largest atomic radius in its period?

1. The covalent radius of Lithium is 123 pm, its metallic radius will be? (More/Less) +

Correct Answer

More than 123 pm

Explanation

The metallic radius of Lithium is greater than its covalent radius. The covalent radius is defined as approximately half the internuclear distance between two covalently bonded lithium atoms.

Covalent radius = 123 pm

The metallic radius, however, is related to the distance from the nucleus of a metal atom to the boundary of its metallic lattice and is generally larger than the covalent radius.

Covalent Radius 123 pm
Smaller

Metallic Radius > 123 pm
Larger

Therefore:

Metallic radius > Covalent radius

So the answer is:

MORE

JEE-Level Concept

For many metallic elements:

Metallic radius > Covalent radius

The metallic radius is measured considering the arrangement of atoms in the metallic crystal lattice, whereas covalent radius is based on the distance between bonded atoms. Therefore, if the covalent radius of Li is 123 pm, its metallic radius must be greater than 123 pm.

Important: The question asks only whether it is more or less, so an exact numerical metallic radius is not required.

Quick Trick

Remember:

Metallic radius > Covalent radius

Thus:

123 pm (covalent) → Metallic radius = MORE

30 Related JEE-Level MCQs with Solutions

1. If the covalent radius of Li is 123 pm, its metallic radius is generally:

A. Less than 123 pm

B. Greater than 123 pm

C. Equal to 123 pm

D. Zero

Answer: B. Greater than 123 pm

2. Covalent radius is approximately half of:

A. Atomic mass

B. Internuclear distance between two identical bonded atoms

C. Nuclear radius

D. Ionic charge

Answer: B

3. Metallic radius is associated with atoms arranged in:

A. Molecular gas

B. Metallic crystal lattice

C. Ionic solution only

D. Vacuum only

Answer: B

4. Which radius is generally larger for a metal?

A. Metallic radius

B. Covalent radius

C. Nuclear radius

D. None

Answer: A

5. The covalent radius of Li is given as:

A. 100 pm

B. 113 pm

C. 123 pm

D. 152 pm

Answer: C. 123 pm

6. If r_covalent = 123 pm, then r_metallic is:

A. <123 pm

B. >123 pm

C. =123 pm

D. Always zero

Answer: B

7. Covalent radius is most directly related to:

A. Covalent bond distance

B. Ionic bond energy only

C. Atomic mass

D. Melting point

Answer: A

8. Metallic radius is determined from the distance between:

A. Nuclei of neighbouring metal atoms in a lattice

B. Electrons only

C. Protons only

D. Isolated nuclei in vacuum

Answer: A

9. The symbol pm represents:

A. Picometre

B. Per metre

C. Proton mass

D. Pressure metre

Answer: A. Picometre

10. 1 pm is equal to:

A. 10⁻⁶ m

B. 10⁻⁹ m

C. 10⁻¹² m

D. 10⁻¹⁵ m

Answer: C. 10⁻¹² m

11. Which radius is based on a covalent bond?

A. Covalent radius

B. Metallic radius

C. Van der Waals radius

D. Nuclear radius

Answer: A

12. Metallic radius is especially applicable to:

A. Metals

B. Noble gases only

C. Non-metals only

D. Molecules only

Answer: A

13. Which radius is related to half the distance between two bonded identical atoms?

A. Metallic radius

B. Covalent radius

C. Ionic radius

D. Crystal radius

Answer: B

14. If the internuclear distance in Li₂ is 246 pm, the covalent radius of Li is:

A. 123 pm

B. 246 pm

C. 492 pm

D. 61.5 pm

Answer: A. 123 pm

15. The metallic radius generally exceeds the covalent radius because:

A. Metallic bonding involves a lattice arrangement

B. Nucleus becomes larger

C. Electrons disappear

D. Atomic number becomes zero

Answer: A

16. Which factor strongly influences atomic radius?

A. Effective nuclear charge

B. Only atomic mass

C. Only neutron number

D. Colour

Answer: A

17. Across a period, atomic radius generally:

A. Increases

B. Decreases

C. Remains constant

D. Becomes infinite

Answer: B

18. Down a group, atomic radius generally:

A. Decreases

B. Increases

C. Remains constant

D. Becomes zero

Answer: B

19. Lithium belongs to:

A. Group 1

B. Group 2

C. Group 17

D. Group 18

Answer: A. Group 1

20. The atomic number of Li is:

A. 1

B. 2

C. 3

D. 4

Answer: C. 3

21. The electronic configuration of Li is:

A. 1s²

B. 1s²2s¹

C. 1s²2p¹

D. 1s²2s²

Answer: B

22. Which radius is normally smallest among these for a given atom?

A. Metallic radius

B. Covalent radius

C. Van der Waals radius

D. All equal

Answer: B, in the usual comparison for bonded atoms; exact radius definitions depend on structure.

23. Van der Waals radius is generally:

A. Smaller than covalent radius

B. Larger than covalent radius

C. Always equal to covalent radius

D. Zero

Answer: B

24. Metallic radius is obtained using atoms in:

A. Metallic crystal

B. Isolated gas only

C. Covalent molecule only

D. Ionic solution only

Answer: A

25. Which property decreases when effective nuclear charge increases?

A. Atomic radius

B. Nuclear charge

C. Atomic number

D. Number of protons

Answer: A. Atomic radius

26. The metallic radius of an element is most closely related to its:

A. Metallic crystal structure

B. Atomic mass alone

C. Melting point alone

D. Ionization energy alone

Answer: A

27. If atomic radius decreases across a period, the effective nuclear charge generally:

A. Increases

B. Decreases

C. Remains zero

D. Becomes negative

Answer: A

28. Which statement is correct?

A. Metallic radius is generally larger than covalent radius for a metal

B. Metallic radius is always zero

C. Covalent radius is always larger than every other radius

D. Radius is independent of bonding

Answer: A

29. The unit commonly used for atomic radii is:

A. kg

B. pm

C. mol

D. K

Answer: B. pm

30. For the given question, the correct word is:

A. Less

B. More

C. Equal

D. Zero

Answer: B. More

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