Identify the following elements from their electron configurations: Element A: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 Element B: 1s2 2s2 2p6 3s2 3p4 Element C: 1s2 2s2 2p6 3s1 Element D: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 Element A is Kr; Element B is S, Element C is Na, Element D is Ba Element A is Ne; Element B is O, Element C is Li, Element D is Sr Element A is Kr; Element B is S, Element C is K, Element D is Ca Element A is Ar; Element B is S, Element C is Na, Element D is Ba
The Correct Answer and Explanation is:
Correct Answer:
Element A is Kr; Element B is S; Element C is Na; Element D is Ba
Explanation:
To identify elements based on their electron configurations, we analyze how electrons fill the atomic orbitals in the order of increasing energy levels using the Aufbau principle. Here’s a breakdown of each:
Element A:
Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
- Count the electrons: 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 = 36 electrons
- The element with atomic number 36 is Krypton (Kr), a noble gas.
So, Element A is Kr.
Element B:
Configuration: 1s² 2s² 2p⁶ 3s² 3p⁴
- Count the electrons: 2 + 2 + 6 + 2 + 4 = 16 electrons
- The element with atomic number 16 is Sulfur (S), a nonmetal in group 16.
So, Element B is S.
Element C:
Configuration: 1s² 2s² 2p⁶ 3s¹
- Count the electrons: 2 + 2 + 6 + 1 = 11 electrons
- The element with atomic number 11 is Sodium (Na), an alkali metal.
So, Element C is Na.
Element D:
Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s²
- Count the electrons: 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 + 10 + 6 + 2 = 56 electrons
- The element with atomic number 56 is Barium (Ba), an alkaline earth metal.
So, Element D is Ba.
Final Answer:
✅ Element A is Kr; Element B is S; Element C is Na; Element D is Ba
