Topic 6: Predictive Table

Sub-topic 6.1: Element Classification

Learning Outcomes

1. Identify and understand the position of periods, groups, and blocks in the predictive table.
2. Use electronic configuration to determine the position of an element in the predictive table.

Introduction to the Predictive Table

• The predictive table contains all chemical elements arranged according to increasing proton numbers (atomic numbers).
• There are three main blocks in the predictive table: S block, P block, and D block.
• S block includes Groups 1 & 2, P block includes Groups 13 to 18, and D block includes Groups 3 to 12.

Determining the Element Block

• S Block: Elements with the last electron in the S orbital.
• P Block: Elements with the last electron in the P orbital.
• D Block: Elements with the last electron in the D orbital.
• Example: Carbon (6 protons) has the electron configuration 1s² 2s² 2p⁴, located in the P block.

Determining the Element Group

• The element group is determined based on valence electrons.
• S Block: Group number is the same as the number of valence electrons.
• P Block: Group number = valence electrons + 10.
• D Block: Group number is the same as the number of valence electrons.
• Example: Sodium (11 protons) in the S block, group 1 because it has 1 valence electron.

Determining the Element Period

• The period of an element is based on the highest shell number occupied by electrons (highest n).
• Example: Oxygen (8 protons) with the configuration 1s² 2s² 2p⁴, in period 2.

How to Recognize the Position of an Element

1. Block: The last electron's orbital determines the block (S, P, D).
2. Group: Based on the number of valence electrons.
3. Period: Based on the highest shell number (highest n).

Example Elements

• Potassium (19 protons): Configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
  • Block: S
  • Group: 1 (valence electron 1)
  • Period: 4
• Bromine (35 protons): Configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵
  • Block: P
  • Group: 17 (valence electrons 7)
  • Period: 4
• Vanadium (23 protons): Configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³
  • Block: D
  • Group: 4 (valence electrons 4)
  • Period: 4

Conclusion

• Period: Determined by the highest n.
• Group: Based on valence electrons.
• Block: Last electron's orbital.
• Use the electronic configuration of a neutral atom to determine the location in the predictive table.

Additional Tips

• Always use the electronic configuration of a neutral atom to determine periods, groups, and blocks.

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