Understanding Electron Configurations

What is the electron configuration of sodium (Na)? a) 1s² 2s² 2p⁶ 3s¹ (correct) b) 1s² 2s² 2p⁶ 3p¹ c) 1s² 2s² 2p⁶ d) 1s² 2s² 2p⁶ 3s²

• 1s² 2s² 2p⁶ 3s¹

• 1s² 2s² 2p⁶ 3d¹

• 1s² 2s² 2p⁶ 3s³

• 1s² 2s² 3s²

Which of the following elements has the electron configuration 1s² 2s² 2p⁶ 3s² 3p³? a) Phosphorus (P) (correct) b) Sulfur (S) c) Aluminum (Al) d) Silicon (Si)

• Bromine (Br)

• Phosphorus (P)

• Argon (Ar)

• Chlorine (Cl)

How many valence electrons does chlorine (Cl) have based on its electron configuration? a) 5 b) 6 c) 7 (Correct) d) 8

• 9

• 10

• 7

• 4

Which principle states that electrons fill orbitals starting with the lowest energy level first? a) Pauli Exclusion Principle b) Hund’s Rule c) Aufbau Principle (Correct) d) Heisenberg Uncertainty Principle

• c) Aufbau Principle

• Noble Gas Configuration

• Electromagnetic Principle

• Quantum Mechanics Principle

What is the correct electron configuration for a magnesium (Mg)? a) 1s² 2s² 2p⁶ 3s² (Correct) b) 1s² 2s² 2p⁶ c) 1s² 2s² 2p⁶ 3s¹ d) 1s² 2s² 2p⁴

• 1s² 2s² 3s²

• 1s² 2s² 2p⁶ 3p²

• 1s² 2s² 2p⁶ 3s³

• 1s² 2s² 2p⁶ 3s²