Chapter 1-8: Introduction to Atomic Structure and Light Emission (Fluorescence & Chemiluminescence)

Flashcards covering key vocabulary related to atomic structure, electron energy levels, fluorescence (including excitation and de-excitation), and its applications such as fireworks and chemiluminescence (like glow sticks and biological luminescence).

Proton

A subatomic particle with a positive charge, found in the nucleus of an atom.

Neutron

A subatomic particle that is neutral (has no charge), found in the nucleus of an atom along with protons.

Atomic Number

Indicates the number of protons an element or atom has, found on the periodic table.

Electrons in a Neutral Atom

The number of electrons must be equal to the number of protons to maintain a neutral charge.

Number of Neutrons Calculation

Determined by subtracting the atomic number from the atomic mass.

Energy Levels (Electron Shells)

Circular, ring-like areas around the nucleus where electrons are likely to be found, influencing their behavior.

n (Energy Level Symbol)

A short form representing the energy level or shell number (e.g., n=1 for the first energy level).

Bohr-Rutherford Model

A model of the atom suggesting that electrons reside in distinct energy levels or rings around the nucleus.

Maximum Electrons (First Energy Level)

The first energy level (n=1) can hold a maximum of two electrons.

Maximum Electrons (Second and Third Energy Levels)

The second and third energy levels can each hold a maximum of eight electrons.

Electron Stability and Distance from Nucleus

Electrons closer to the nucleus experience a stronger attraction to the positive protons, making them more stable.

Electron Excitation

The process where an electron gains energy from an external source and jumps from a lower (ground) energy level to a higher (excited) energy level.

Ground State

The initial, lowest energy level where an electron is normally found in an atom.

Excited State

A higher energy level that an electron occupies temporarily after gaining energy and jumping from its ground state.

External Energy Sources for Electron Excitation

Electrical current, a flame (high temperature), or a high-energy light source.

Light Emission

Occurs when an excited electron falls back down from a higher energy level to a lower energy level, releasing energy in the form of specific colors of light.

Fluorescence

The overall process where an external energy source excites an electron, causing it to jump to a higher energy level, and then emit light as it falls back to its ground state.

Factors Affecting Emitted Light Color

The specific color of light produced depends on how far the excited electron falls back down to its ground state.

High Energy Light

Light with shorter wavelengths, typically perceived as purple and blue colors in the visible spectrum.

Low Energy Light

Light with longer wavelengths, typically perceived as red and orange colors in the visible spectrum.

ROYGBIV Mnemonic

An acronym (Red, Orange, Yellow, Green, Blue, Indigo, Violet) representing the colors of the rainbow, ordered from low to high energy (long to short wavelength).

Atomic Emission Spectra

The unique pattern of colored lines of light produced by specific elements through fluorescence, resulting from electron transitions.

Chemiluminescence

A specific type of fluorescence where the energy required to excite electrons and produce light comes directly from a chemical reaction.

Glow Sticks

An application of chemiluminescence where a chemical reaction between internal compounds (hydrogen peroxide and DPO) excites a dye, causing it to emit a sustained glow.

Hydrogen Peroxide (Glow Sticks)

A compound housed in the inner tube of a glow stick; it reacts with DPO to generate the energy for light emission.

DPO (Diphenyl Oxalate)

A compound in the outer tube of a glow stick that reacts with hydrogen peroxide to provide the energy for luminescence.

Dye (Glow Sticks)

The component in a glow stick that becomes excited by the energy from the chemical reaction, resulting in the visible color of the glow.

Biological Chemiluminescence

Natural processes like the glowing of fireflies and jellyfish, where enzymatic reactions produce energy for light emission.

Luminol (Crime Scene Application)

A chemical used at crime scenes that reacts with iron in blood's hemoglobin via chemiluminescence, producing a blue glow even for invisible blood traces.

Effect of Cold on Chemiluminescence

Lower temperatures slow down the chemical reaction, causing the light to be dimmer but to last for a longer period.

Radioactive Material Fluorescence

Certain radioactive materials (like uranium) fluoresce continuously without an external energy source because their inherent radioactivity provides the energy to excite electrons.