Origins

Biogeochemical Cycles

describe the flow of essential elements from the environment -> living organisms -> environment

Examples of Types of Biogeochemical Cycles

hydrological, carbon, nitrogen, phosphorus

Most abundant element in the universe

hydrogen

2nd Most abundant element in the universe

helium

Lightest elements were produced in

the Big Bang

Stars less massive than the Sun produced

helium (converted from hydrogen)

Stars more massive than the Sun produced

elements up to atomic number 8 (oxygen)

Very massive stars produced ___ via fusion

elements up to atomic number 26

Heaviest elements produced via

supernova

An atom is made up of

protons, neutrons, and electrons

Labels for Atomic Elements

Z = protons (atomic #)

N = neutrons

e = electrons

A = atomic mass (Z + N)

Stability of a nucleus relies on

Spin pairing

Shell binding (orbitals)

Surface tension

Column Repulsion

Binding Energy

the energy that would be required to disassemble the nucleus of an atom into its component parts

Binding Energy Formula

[Am_components-Am_atom] * 1 amu * c²

{Am = atomic mass}

Mass Defect

the difference in mass between an atom and the sum of its components (sum of components weighs more than atom)

2 main forces for atoms

strong nuclear force

electromagnetic force

Iron is so stable because

adding or removing electrons would result in a higher-energy configuration

Isotope

same element has the same number of protons, but different number of neutrons

Two Types of Isotopes

Radioisotopes and Stable Isotopes

Radiation

energy in the form of high-speed particles (or electromagnetic waves or photons)

3 Modes of Decay

Alpha particles

Beta particles

Gamma rays

Alpha Particles

Most densely ionizing, but least penetrating

(won't go through clothes or even dead skin)

Beta Particles

less energetic than alpha, but more penetrating

(cannot travel through dense materials)

Gamma Rays

High-energy electromagnetic energy and most penetrating

Elemental composition of Earth (most common to least)

1. Iron

2. Oxygen

3. Silicon

Humans are made of mostly

Oxygen (then Carbon)