Upload
preston-byrd
View
21
Download
0
Embed Size (px)
DESCRIPTION
SBI 4U1 – Unit 1. Lesson 1 Basic Concepts in Chemistry. Atomic Theory. All living things are made of matter All matter is made of atoms Therefore all living things consist of atoms - PowerPoint PPT Presentation
Citation preview
SBI 4U1 – Unit 1
Lesson 1
Basic Concepts in Chemistry
Atomic Theory
• All living things are made of matter• All matter is made of atoms• Therefore all living things consist of atoms• Therefore all living things are governed
by the same laws of the physical universe that govern the interactions of atoms and molecules
The Laws of Thermodynamics
Basic Chemistry Review
• 1.1 Chemical Fundaments• Bohr Diagrams allow us to determine the valence
or chemically active electrons of an element– Valence number refers to the number of bonds an
element is capable of forming
• X = element symbol• A = # of protons
= # of positive charge
= # of electrons in neutral atoms• Z = atomic mass
XA
Z
Basic Chemistry Review - Ions
• Elements or compounds that have acquired an electric charge
• Due to the gain or loss of electrons– E.g. NaCl will dissociate in solution to form to
monatomic ions:– Na+ ions have lost one electron to the chlorine ions– Cl- ions have gained one electron from sodium ions
Basic Chemistry Review - Ions
• Many biologically active ions are polyatomic– Phosphate PO4
3-
– Sulfate SO42-
– Nitrate NO3-
– Hydroxyl OH-
Basic Chemistry Review - Isotopes• Atoms of elements with an atomic mass that is
different from the most commonly found form• E.g. 3 isotopes of carbon
– C – 12; 6 protons, 6 neutrons– C – 13; 6 protons, 7 neutrons– C – 14; 6 protons, 8 neutrons
• Isotopes have a variety of uses– Diagnosis – radioactive isotopes can be used to “light
up” organs and tissues of interest– Treatment – used to treat a variety of soft tissue
disorders including cancers– Research – radioactive isotopes can be used to track
changes to biological molecules in metabolic pathways
Basic Chemistry Review - Bonding
• Bonding allows atoms to form stable configurations as larger compounds
• A sharing or distribution of valence electrons in order to stabilize outer electron orbitals
• Two main types of bonds– Intramolecular – within the molecule
• Ionic• Covalent• Polar Covalent
– Intermolecular – between molecules• Di-pole Hydrogen bonds• Vander Waals
Basic Chemistry Review - Bonding
Electronegativity• A measure of the tendency of a particle to attract
a bonding pair of electrons• Scale ranges from 0 to 4.0• Cesium has the lowest value 0.7• Flourine the highest at 3.98• ΔE values determine the type of bond• Pauling Scale is generally used to determine
electronegativity values as experienced by atoms in molecules
Basic Chemistry Review - Bonding
Ionic Bonds– ΔE>1.7 – disassociate in water– Useful for biological reactions but not for creating
biological structures
Covalent Bonds– ΔE = 0 – very strong and stable – Can be single, double or triple– Most common form of bonding in biological
molecules
Polar Covalent– 0>ΔE<1.7 – Similar to covalent but the distribution of electrons is
not equal resulting in a localized electric charge