SCIE-C3_16S - SCIE1110 Great Ideas in Science Spring 2016...

Info icon This preview shows pages 1–4. Sign up to view the full content.

SCIE1110: Great Ideas in Science Spring 2016 Chemistry Module: Prof. Ian D. Williams Rm 6005 CYT [email protected] Lecture 3. Chemical Bonding
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Lecture 2 Periodic Table: Summary By end of 18 th century concept of elements well established thanks to Lavoisier , who had disproved Phlogiston Theory. Dalton proposed new Atomic Theory by 1808. Though most of his ideas not entirely correct, they were a useful working model for chemistry of elements and their compounds . In chemical reactions atoms are neither created or destroyed, but change in their combinations with each other. In 1807 Davy made breakthrough in isolating many electropositive metal elements , using electrochemistry to produce Potassium (potash), Sodium (Soda), Magnesium and Calcium. As more elements discovered scientists speculated about what made them different and questioned how many there could be. Prout theorized that all elements were multiples of hydrogen, the simplest atom. He was close number of protons do determine element type Swede Berzelius took Davy‘s work further & with reactive potassium could isolate others, such as silicon , from their salts. He introduced modern chemical symbols for the elements and a simple integer notation for chemical formulas (e.g. H 2 O for water). Berzelius‘ greatest contribution was the first accurate determinations of relative atomic weights . Atoms of an element are not identical since they can have different isotopes, which would later explain unusual fractional masses, such as for chlorine . C3.2 SCIE 1110 Spring 2016
Image of page 2