Atomic Theory, Subatomic Mass, and Elements of Life

Vocabulary flashcards covering the history of atomic models, subatomic particle properties, electromagnetic radiation formulas, and essential biological elements.

Aristotle's View of Matter

The philosophical belief originating in BC from the philosopher Aristotle that all matter is composed of Earth, Water, Air, and Fire.

Atomos

The Greek word meaning indivisible, coined in BC by the Greek philosopher Democritus who proposed that the smallest particle of matter is an atom.

Law of Conservation of Matter

A fundamental law introduced in the 1700s by Antoine Lavoisier stating that matter can not be created nor destroyed.

Law of Constant/Definite Proportions

A law established in 1800 by Proust stating that a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound.

Law of Multiple Proportions

Dalton's law stating that if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers.

Dalton's Atomic Model (Atom #1)

An early 1800 atomic model created by John Dalton, known as the father of modern chemistry, which conceptualized the atom as a dense sphere.

Plum Pudding Model (Atom #2)

An atomic model established in 1897 by J.J. Thomson based on the idea that an atom contains both positive and negative components.

Cathode Ray

A negatively charged stream of particles composed of electrons that emerges from a negatively charged cathode, possesses mass, and can be deflected or attracted by a magnetic field.

Nuclear Model (Atom #3)

The 1911 atomic model introduced by Rutherford which established that an atom has both positive and negative components and features a dense nucleus.

Gold Foil Experiment

Rutherford's 1911 experiment where alpha particles from Polonium ($+$) were fired at a thin gold sheet, proving atoms are mostly empty space because most went through, while some hit a dense nucleus and bounced off.

Planetary Model (Atom #4)

The 1913 atomic model developed by Danish physicist Niels Bohr depicting electron orbits around the nucleus.

Spectroscope

An instrument equipped with a prism placed by the eye with its slit facing away, designed to split light and reveal an element's unique line emission spectrum.

Excited State

The state an electron enters when energy is absorbed and the electron moves up to a higher energy level.

Ground State

The state reached when an electron releases energy in the form of light and moves down to a lower energy level.

Real Mass

The actual physical mass of subatomic particles, specifically $1.7 \times 10^{-27}\,kg$ for protons and neutrons, and $9.1 \times 10^{-31}\,kg$ for electrons.

Relative Atomic Mass

A comparative measurement relating the masses of subatomic particles, where Proton = $1$, Neutron = $1$, and Electron = $1/2000$.

Weighted Average Atomic Mass

The most accurate way to describe atomic mass, determined by converting the percent abundance of each isotope into a decimal, multiplying by its atomic mass unit, and adding all sums together.

Speed of Light ($c$)

A fundamental constant equal to $3.00 \times 10^8\,m/s$, related to radiation by the equation $c = (\text{wavelength})(\text{frequency})$.

Photon

A discrete packet of light.

CHNOPS

The group of six elements that make life possible and constitute $97\%$ of the human body's weight: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur.

Adenosinetriphosphate (ATP)

An essential biological molecule that incorporates phosphorus, which makes up $1\%$ of the human body.

Trace Elements

Elements making up the remaining $3\%$ of body weight, including Zinc and Magnesium for energy metabolism, and Potassium and Sodium for nervous system function.