Notes: The Chemicals of Life

Elements Everything is made up of ELEMENTS, the SIMPLEST chemical substance and CAN’T be BROKEN down Are elements biotic or abiotic?

Essential Elements ONLY 25 elements are ESSENTIAL to living organisms 99% of the human body is made up of: oxygen (65%) carbon (18%) hydrogen (10%) nitrogen (3%) calcium (1.5%) phosphorous (1%) Most of the human body is made up of water, H2O, with cells consisting of 65-90% water by weight. Therefore, it isn't surprising that most of a human body's mass is oxygen. Carbon, the basic unit for organic molecules, comes in second. 99% of the mass of the human body is made up of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Oxygen (65%) Carbon (18%) Hydrogen (10%) Nitrogen (3%) Calcium (1.5%) Phosphorus (1.0%) Potassium (0.35%) Sulfur (0.25%) Sodium (0.15%) Magnesium (0.05%) Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%) Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

Trace Elements TRACE elements are found in living organisms in very SMALL amounts. Potassium Sulfur Sodium Magnesium Copper Zinc Selenium Molybdenum Fluorine Chlorine Iodine Manganese Cobalt Iron Lithium Strontium Aluminum Silicon Lead Vanadium Arsenic Bromine

Atoms ELEMENT = Same ATOMS! They are pure substances

Atom Atoms have PROTONS, NEUTRONS, and ELECTRONS The nucleus (center) contains PROTONS and NEUTRONS PROTONS = + NEUTRONS = NO charge

Atom Structure

Electrons ELECTRONS are found around the nucleus in a CLOUD ELECTRONS are negative (-) Electrons = Protons

Who has heard of The Periodic Table of Elements?

Hydrogen What is the symbol used to represent hydrogen? What is hydrogen’s atomic # (# of protons)? What is hydrogen’s atomic mass (Protons PLUS neutrons)?

Potassium What is Potassium’s symbol? How many protons does potassium have? How many neutrons? How many electrons?

Calcium What is the symbol for calcium? _____ How many electrons? _____ How many protons? _____ How many neutrons? _____ Atomic mass? _____

Krypton Symbol? _____ Protons? _____ Neutrons? _____ Electrons? _____ Mass? _____ Isotopes of the Element Krypton with a Known Natural Abundance (stable) Mass Number---Natural Abundance 78---0.35% 80---2.28% ---11.58% ---11.49% 84---57.00% 86---17.30% 37 Known Isotopes of the Element Krypton Isotope mass numbers run from 69 to 100 What is this?

Isotopes Atoms of the same element that have different number of NEUTRONS Ex: Carbon 12 = 6 protons and 6 neutrons Carbon 13 = 6 protons and 7 neutrons Carbon 14 = 6 protons and 8 neutrons The nucleus of most isotopes are unstable and often break giving off RADIATION when it breaks down

Ways to use isotopes Diagnose or treat diseases (detection of radiation can indicate cancer) Thyroid gland functioning properly (use radioactive Iodine, absorbed by thyroid gland) Determine the “HALF-LIFE” of an item (fossil, rock, etc)