“CHEMISTRY OF LIFE” Chapter 6

ELEMENTS: A SUBSTANCE THAT CAN NOT BE BROKEN DOWN INTO A SIMPlER SUBSTANCE. ELEMENTS CONSIST OF ONE TYPE OF ATOM. These four elements make up 96% of living things c H 1 1 O 16 8 N 14 7 CARBON HYDROGEN OXYGEN NITROGEN

ATOMS: aTOm: Greek for “unable to be cut” Atoms are the building blocks of an element. Atoms consist of three sub- atomic particles: – Protons: Positively charged particles ( p+) – NEUTRONS: Particles with no charge (n°) – Electrons: negatively charged particles (e-)

ATOMIC SYMBOLS: Reading the atomic symbol Atomic Number = The Number of Protons and Also the Number of Electrons Atomic Mass = The Number of Protons Added to the Number of Neutrons The small # is always the Atomic Number & the large # is always the Mass Number !

Energy levels: Protons (p+) and Neutrons (n°) are located in the nucleus  Electrons are located in Energy Orbitals outside of the nucleus *I st Energy Orbital= 2e- *2 nd Energy Orbital= 8e- *3 rd Energy Orbital= 8e-

OK….Let’s Practice! 96% of Your Body Is Made Up Of Four Elements on the Periodic Table: – C Carbon – H Hydrogen – O Oxygen – N Nitrogen Construct the Atomic Structure Diagram for Each of these elements! We will Do the First Two Together

Ions Ion: an atom that has lost or gained electrons – Electron lost → positive (+) ion = CATION – Electron gained → negative (-) ion = ANION

Isotopes Isotope: an atom that has gained or lost a neutron – Keeps same # protons & electrons – Electrical charge DOES NOT CHANGE –