Determine the period, group, and block for an element with Z = 37.

📚 Chapter: Classification of Elements and Periodicity in Properties

📘 Detailed Solution

🔵 Step 1: Identify the Element

Atomic number Z = 37 corresponds to the element Rubidium (Rb).

Z = 37 → Rubidium (Rb)

🟢 Step 2: Write the Electronic Configuration

The electronic configuration of Rubidium is:

Rb = [Kr] 5s¹

The complete configuration is:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹

🎬 Electronic Configuration Animation

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹

↓

[Kr] 5s¹

🟣 Step 3: Determine the Period

The period is determined by the highest principal quantum number (n) present in the electronic configuration.

For Rb:

Highest n = 5
Therefore, Period = 5

🟠 Step 4: Determine the Group

Rubidium has one electron in its outermost shell:

5s¹

Elements having the outer configuration ns¹ belong to Group 1.

Group = 1

🟢 Step 5: Determine the Block

The last electron enters the s-subshell. Therefore, the element belongs to the s-block.

Block = s-block

✅ Final Answer

Z = 37 → Rubidium (Rb)

Period = 5
Group = 1
Block = s-block

📝 20 MCQs – Practice

1. The element with atomic number 37 is:

A) Potassium

B) Rubidium

C) Strontium

D) Caesium

✅ Answer

B) Rubidium

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2. The symbol of element Z = 37 is:

A) Rb

B) Ru

C) Ra

D) Rh

✅ Answer

A) Rb

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3. The electronic configuration of Rb is:

A) [Kr] 5s¹

B) [Ar] 4s¹

C) [Kr] 4d¹

D) [Xe] 6s¹

✅ Answer

A) [Kr] 5s¹

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4. Rb belongs to which period?

A) 3

B) 4

C) 5

D) 6

✅ Answer

C) 5

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5. Rb belongs to which group?

A) 1

B) 2

C) 17

D) 18

✅ Answer

A) 1

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6. Rb belongs to which block?

A) p-block

B) d-block

C) s-block

D) f-block

✅ Answer

C) s-block

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7. The last electron of Rb enters:

A) 4p

B) 5s

C) 4d

D) 5p

✅ Answer

B) 5s

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8. The valence-shell configuration of Rb is:

A) 5s¹

B) 5s²

C) 5p¹

D) 4d¹

✅ Answer

A) 5s¹

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9. The highest principal quantum number in Rb is:

A) 3

B) 4

C) 5

D) 6

✅ Answer

C) 5

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10. Group 1 elements generally have outer configuration:

A) ns¹

B) ns²

C) ns²np⁵

D) ns²np⁶

✅ Answer

A) ns¹

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11. Which element is in the same group as Rb?

A) Ca

B) K

C) Br

D) Kr

✅ Answer

B) K

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12. Rb is a:

A) Noble gas

B) Alkali metal

C) Halogen

D) Transition metal

✅ Answer

B) Alkali metal

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13. Which block is determined by the subshell receiving the differentiating electron?

A) s-block

B) p-block

C) d-block

D) All of these

✅ Answer

D) All of these

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14. The atomic number immediately before Rb is:

A) 35

B) 36

C) 38

D) 39

✅ Answer

B) 36

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15. Atomic number 36 represents:

A) Kr

B) Rb

C) Sr

D) Br

✅ Answer

A) Kr

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16. Rb has how many valence electrons?

A) 1

B) 2

C) 7

D) 8

✅ Answer

A) 1

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17. Rb is located in the:

A) Leftmost part of the periodic table

B) Rightmost part

C) Middle d-block

D) f-block

✅ Answer

A) Leftmost part

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18. Which orbital is being filled in Rb?

A) 4s

B) 4p

C) 5s

D) 3d

✅ Answer

C) 5s

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19. Rb has one electron outside the:

A) [Ne] core

B) [Ar] core

C) [Kr] core

D) [Xe] core

✅ Answer

C) [Kr] core

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20. The correct classification for Z = 37 is:

A) Period 4, Group 2, p-block

B) Period 5, Group 1, s-block

C) Period 5, Group 2, s-block

D) Period 4, Group 1, d-block

✅ Answer

B) Period 5, Group 1, s-block

Q1. Identify the element with Z = 37 and write its electronic configuration.

Solution: Z = 37 is Rubidium (Rb). Its configuration is [Kr] 5s¹.

Q2. What is the group and block of Rb?

Solution: Rb has outer configuration 5s¹. Therefore, it belongs to Group 1 and s-block.

Q3. Determine the period of Rb.

Solution: The highest value of n is 5 in 5s¹. Hence, Rb belongs to Period 5.

Q1. Determine the period, group and block of Z = 37.

Solution:

1. Z = 37 → Rb.
2. Electronic configuration = [Kr] 5s¹.
3. Highest n = 5 → Period 5; ns¹ → Group 1; last electron enters s-subshell → s-block.

Period = 5 | Group = 1 | Block = s-block

Q2. Explain how electronic configuration helps in locating Rb in the periodic table.

Solution: The highest shell number gives the period. The outermost 5s¹ configuration gives Group 1, and the differentiating electron enters the s-subshell, giving s-block.

Q1. Write the complete electronic configuration of Z = 37 and determine its position in the periodic table.

Solution:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹

Highest n = 5, therefore Period 5. The valence configuration is 5s¹, therefore Group 1. The last electron enters an s-orbital, therefore s-block.

Rb → Period 5 → Group 1 → s-block

Q1. Explain systematically how the position of an element with atomic number 37 is determined in the periodic table.

Solution:

1. Atomic number 37 corresponds to Rubidium (Rb).
2. Its electronic configuration is [Kr] 5s¹.
3. The highest principal quantum number is 5, so it belongs to Period 5.
4. The outermost configuration is ns¹, so it belongs to Group 1.
5. The differentiating electron enters the s-subshell, so it belongs to the s-block.

Final Position: Period 5, Group 1, s-block

Q1. For an element having atomic number 37, determine its electronic configuration, element name, period, group and block. Explain each step.

Solution:

Step 1 – Identify the element:

Z = 37 → Rubidium (Rb)

Step 2 – Electronic configuration:

Rb = [Kr] 5s¹

Step 3 – Determine the period:

The highest principal quantum number in the configuration is n = 5. Therefore, the element belongs to Period 5.

Step 4 – Determine the group:

The outermost configuration is 5s¹. Elements with ns¹ configuration belong to Group 1.

Step 5 – Determine the block:

The differentiating electron enters the s-subshell. Therefore, the element belongs to the s-block.

Step 6 – Final classification:

Z = 37 → Rb

Period = 5
Group = 1
Block = s-block
Type = Alkali Metal

🎯 Quick Revision

Z = 37
Element = Rubidium (Rb)
Configuration = [Kr] 5s¹
Period = 5
Group = 1
Block = s-block