Study Guide: Electrons and the Electron Cloud

Practice flashcards covering core vocabulary, electron configurations, quantum principles, and the electromagnetic spectrum from the Electrons and the Electron Cloud study guide.

Why are the first 20 elements of the periodic table sometimes referred to as representative elements?

Because their electrons neatly obey the rules of electron placement.

How does a Bohr model represent the arrangement of electrons in an atom?

It shows a nucleus surrounded by circles with electrons represented by dots, showing the relative energy level and distance from the nucleus.

How does energy change with distance from the nucleus in the electron cloud?

The level closest to the nucleus has the least energy, and the energy increases with distance from the nucleus.

What are valence electrons?

Electrons located in the outermost energy level of an atom.

What does an electron configuration specify?

It specifies which energy levels and sublevels are filled, as well as the total number of electrons in each sublevel.

What does the Aufbau principle state?

Lower energy levels fill before beginning to fill orbitals at higher energies.

What does Hund's rule dictate regarding electron placement in orbitals?

Electrons spread out into each orbital at a particular sublevel before pairing.

What does the Pauli exclusion principle state about electrons sharing an orbital?

Electrons within an orbital must spin in opposite directions.

What constitutes the electromagnetic spectrum?

Various types of electromagnetic radiation, such as radio waves, visible light, and UV light.

What is the speed of light ($c$) at which all electromagnetic radiation travels?

$$3.0 \times 10^8\,\text{m/s}$$

What is wavelength ($\lambda$) and in what unit is it measured?

The distance between the peaks of the waves, measured in meters.

What is frequency ($f$) and what are its units of measurement?

The number of waves that pass a fixed point per second, measured in hertz ($\text{Hz}$) or $1/\text{s}$.

How is the energy ($E$) of an electron related to its frequency and wavelength?

It is directly proportional to its frequency and inversely proportional to its wavelength.

What unit is used to measure the energy ($E$) of an electron?

Joule ($\text{J}$).

How is an emission spectrum produced?

When electrons absorb energy, jump to a higher energy level, and then fall back down to a more stable state, releasing the excess energy as photons of light with characteristic energies and frequencies.

Why is an emission spectrum compared to a fingerprint?

Because it is as unique to each element as a fingerprint.