Electron Configuration

What does the Aufbau Principle state about electron configuration?

• Electrons fill orbitals starting from the lowest energy level to the highest.

• Electrons fill orbitals randomly without any order.

• Electrons occupy the highest energy levels first before lower ones.

• Electrons are placed in pairs within the same orbital before moving on.

Explain the Pauli Exclusion Principle in terms of electron orbitals.

• Electrons can share the same orbital if they have the same spin.

• Each orbital can hold up to four electrons with any spin configuration.

• The Pauli Exclusion Principle allows three electrons in one orbital.

• The Pauli Exclusion Principle states that no two electrons can occupy the same quantum state within an atom, leading to a maximum of two electrons per orbital with opposite spins.

How does Hund's Rule apply when filling orbitals of the same energy level?

• Electrons fill degenerate orbitals singly first, with parallel spins, before pairing.

• Electrons fill all orbitals in pairs before any are singly occupied.

• Electrons occupy the lowest energy orbitals first, regardless of spin.

• Electrons fill degenerate orbitals in pairs with opposite spins first.

Draw an orbital diagram for the element oxygen (O).

• 1s: ↑ 2s: ↑↓ 2p: ↑↓ ↑↓

• 1s: ↑↓ 2s: ↑↓ 2p: ↑ ↑ ↑

• 1s: ↑↓ 2s: ↑↓ 2p: ↑↓ ↑ ↑

• 1s: ↑↓ 2s: ↑ 2p: ↑↓ ↑↓

What are valence electrons and why are they important?

• Valence electrons are the protons in an atom, essential for mass and weight.

• Valence electrons are the electrons in the nucleus, vital for atomic structure.

• Valence electrons are the outermost electrons of an atom, important for chemical bonding and reactivity.

• Valence electrons are the innermost electrons of an atom, crucial for nuclear stability.

According to the Aufbau Principle, which orbital is filled first: 3s or 4s?

• 4s

• 3d

• 3s

• 4p

How many electrons can occupy a single orbital according to the Pauli Exclusion Principle?

• 2

• 4

• 3

• 1

What is the significance of Hund's Rule in determining the electron configuration of an atom?

• Hund's Rule is significant because it ensures that electrons fill degenerate orbitals singly first, leading to a more stable electron configuration.

• Hund's Rule states that electrons must fill all orbitals completely before pairing up.

• Hund's Rule suggests that electrons will always pair up in the same orbital before moving to the next.

• Hund's Rule indicates that electrons prefer to occupy the lowest energy level available first.

Illustrate the orbital diagram for nitrogen (N) and label the valence electrons.

• Orbital diagram: 1s: ↑↓, 2s: ↑, 2p: ↑↑↑↑ (Valence electrons: 2s¹ 2p⁴)

• Orbital diagram: 1s: ↑↓, 2s: ↑↓, 2p: ↑↑↑↑ (Valence electrons: 2s² 2p⁴)

• Orbital diagram: 1s: ↑↓, 2s: ↑↓, 2p: ↑↑ (Valence electrons: 2s² 2p²)

• Orbital diagram: 1s: ↑↓, 2s: ↑↓, 2p: ↑↑↑ (Valence electrons: 2s² 2p³)

How do you determine the number of valence electrons in an element from the periodic table?

• Valence electrons are determined by the element's mass number.

• The number of valence electrons is equal to the atomic number.

• The number of valence electrons corresponds to the group number for main group elements.

• You find valence electrons by subtracting the group number from eight.