Teacher Notes This PPT was revised June 10, This PPT is a review on the atomic characteristics of the four main essential elements hydrogen, carbon, oxygen, and nitrogen. This information is for introduction/ review only, not for testing purposes.

collection of compounds forming a living unit; smallest unit of an organism that can be considered living chemical combination of two or more elements in definite proportions smallest unit of matter that retains its chemical properties a substance made up of only one type of atom (periodic table of elements) bonding between atoms of 1 or more elements; smallest unit of a compound

Can a substance be both an element and a molecule? molecular levels of organization from smallest to cell atom element molecule compounds cell NaCl CO 2 C 6 H 12 O 6 Can a substance be both a molecule and a compound? What is O 2 ? O 3 ?

e CHNOPS Carbon Hydrogen NitrogenOxygen PhosphorusSulfur H

Carbon is an element. What is carbon? C commonly found as graphite, diamonds atomic number (6 protons) is constant  atomic mass varies number of neutrons may vary (6, 7, 8)  atomic mass varies e

+ C 6 carbon S How many protons? atomic number How many neutrons? + 6 atomic mass = How many energy levels? How many electrons? 6

What properties are used to position carbon on the periodic table? # of protons = atomic number # of energy levels 1 2 C e

What is hydrogen? Hydrogen is an element. H the lightest element most abundant element in the universe makes up 90% of the universe by weight a colorless gas e

H G hydrogen How many electrons? How many protons?1 atomic number How many neutrons?0 = atomic mass How many energy levels? 1

Which properties are used to position hydrogen on the periodic table? # of protons = atomic number + # of energy levels H e

Oxygen (O 2 ) is an essential element in many compounds and is used by most organisms for respiration (to get energy for metabolism) What is oxygen? Oxygen is an element. O Ozone (O 3 )-a highly active compound in the atmosphere occurring in a thin,3 mm layer that prevents harmful UV rays from reaching the earth.

O G oxygen How many electrons? How many neutrons? How many protons?8 atomic number = atomic mass How many energy levels? 2

Which properties are used to position oxygen on the periodic table? # of protons = atomic number # of energy levels O

What is nitrogen? Nitrogen is an element. N proteins contain N most abundant element in the air must be “fixed” before it can be used an odorless gas H Li Na K Rb Fr Cs Be Mg Ca Sr Ra Ba Sc Y Ac La Ti Zr Rf Hf V Nb Ha Ta Cr Mo W Mn Tc Re Fe Ru Os Ni Pd Pt Co Rh Ir Cu Ag Au Zn Cd Hg B Al Ga In Ti C Si Ge Sn Pb O S Se Te Po F Cl Br I At He Ne Ar Kr Xe Rn P As Sb Bi N N N

N G nitrogen How many electrons? How many neutrons? How many protons?7 atomic number = atomic mass How many energy levels? 2 N N

Which properties are used to position nitrogen on the periodic table? # of protons = atomic number # of energy levels N N N H Li Na K Rb Fr Cs Be Mg Ca Sr Ra Ba Sc Y Ac La Ti Zr Rf Hf V Nb Ha Ta Cr Mo W Mn Tc Re Fe Ru Os Ni Pd Pt Co Rh Ir Cu Ag Au Zn Cd Hg B Al Ga In Ti C Si Ge Sn Pb O S Se Te Po F Cl Br I At He Ne Ar Kr Xe Rn P As Sb Bi N

ORGANIC compounds contain a carbon-hydrogen bond (C 6 H 12 O 6, CH 4 ) INORGANIC compounds do not contain a carbon-hydrogen bonds (CO 2, H 2 O)

lipid C,O,H carbohydrate C,O,H protein C,O,H,N nucleic acids C,O,H,N,P water H 2 O most important inorganic compound in living things most cellular processes take place in water solutions excellent solvent because of polarity (substances dissolve in water) carbon dioxide CO 2