1.3Electrons, Energy Levels & Atomic Orbitals

These flashcards cover key concepts from the lecture on electron configurations, energy levels, and atomic orbitals.

What is the arrangement of electrons in an atom called?

The electronic configuration.

What do principal quantum numbers (n) indicate?

They are used to number the energy levels or quantum shells.

How many electrons can the n = 2 principal quantum shell hold?

Up to 8 electrons.

What letters are used to label sub-shells?

s, p, d, and f.

What determines the energy of electrons in sub-shells?

The energy of the electrons in the sub-shells increases in the order s < p < d < f.

How many orbitals does an s sub-shell contain?

1 orbital.

What shape do s orbitals have?

Spherical.

What shape do p orbitals have?

Dumbbell-shaped.

What is the ground state of an atom?

The most stable electronic configuration with the lowest amount of energy.

How are electrons arranged in orbitals when they occupy the same sub-shell?

They occupy separate orbitals first and have the same spin to minimize repulsion.

What is a free radical?

A species with one or more unpaired electrons.

What happens when two electrons occupy the same orbital?

They must have opposite spins and experience spin-pair repulsion.

What is the maximum number of electrons that can occupy a p sub-shell?

6 electrons (3 orbitals x 2 electrons/orbital).

What is an exception to the filling order of orbitals in transition metals?

The 4s orbital is filled before the 3d orbital.

How does the noble gas notation simplify electron configuration?

It uses the symbol of the nearest noble gas in brackets to represent inner electrons.

What is the electronic configuration of Iron (Fe)?

Full configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶; Shorthand: [Ar] 4s² 3d⁶.

What is the electronic configuration for the Calcium ion (Ca²⁺)?

Full configuration: 1s² 2s² 2p⁶ 3s² 3p⁶; Shorthand: [Ar].

Why does Chromium have a different electron configuration from the expected?

Its configuration [Ar] 3d⁵ 4s¹ is more stable due to half-filling of the d-subshell.