Study the following electronic configuration of element X and Y X = 1s^2, 2s^2 2p^4 Y = 1s^2, 2s^2 2p^6, 3s^2 3p^6, 4s^1 a) In which group of periodic table does element X lie? [1] b) Write chemical…

a) Group of Element X in the Periodic Table

The electronic configuration of element X is: $$1s^2,2s^{2}2p^4$$

• The valence shell is the second shell (n=2).
• The valence electrons are in the 2s and 2p subshells:
  • $2s^2$ → 2 electrons
  • $2p^4$ → 4 electrons
  • Total valence electrons = 2 + 4 = 6

In the Modern Periodic Table, the group number is determined by the total number of valence electrons (for main group elements).

• Group 16 (or VI A) contains elements with 6 valence electrons (e.g., Oxygen, Sulfur).

Thus, element X lies in Group 16 of the periodic table.

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b) Chemical Nature of Element Y

The electronic configuration of element Y is: $$1s^2,2s^{2}2p^6,3s^{2}3p^6,4s^1$$

• The valence shell is the fourth shell (n=4).
• The valence electron is in the 4s subshell:
  • $4s^1$ → 1 electron in the outermost shell.

Determining Chemical Nature

1. Valency (Combining Capacity):
   • Since Y has 1 valence electron, it tends to lose 1 electron to achieve a stable electronic configuration (like the nearest noble gas, Krypton).
   • Thus, Y forms +1 cations (Y⁺).

K+H₂Ovigorous reactionKOH+H₂

2. Reactivity:

   • Elements with 1 valence electron are highly reactive metals (alkali metals).
   • They react vigorously with water, oxygen, and halogens.

3. Position in the Periodic Table:

   • The configuration matches Potassium (K, Z=19) or Sodium (Na, Z=11) if misassigned, but the given configuration corresponds to Potassium (K).
   • Potassium (K) is an alkali metal (Group 1), which is highly electropositive and basic in nature.

Conclusion

Element Y is a highly reactive metal with basic (alkaline) chemical nature. It belongs to Group 1 (Alkali Metals) and exhibits strong reducing properties due to its tendency to lose the single valence electron.

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Note: If the question expects a one-word answer for part (b), the chemical nature of Y is "basic" (since it forms basic oxides/hydroxides). However, a detailed explanation is provided for full marks in exams like SEE.