CHEMISTRY Chemistry Video Chemistry The study of matter

CHEMISTRY!

Chemistry - Video ● Chemistry – The study of matter and changes in matter ● Matter – Anything that has a mass and occupies space

● Compounds – Two or more elements combined. Ex: H 2 O or Na. Cl

● Element – Pure substance made from one sort of atom. Ex: H or O

● Atom – The smallest unit of matter

Five parts to an atom: ● Nucleus – the centre of the atom – contains neutrons and protons. ○protons – Positive charge (+) ○neutrons – No charge or neutral (0) ○electrons – Negative charge (-) ● Electron shell – the region around the nucleus where the electrons are found.

The Periodic Table

Pre-Periodic Table Chemistry … ● …was a mess!!! ● No organization of elements. ● Difficult to find information. ● Chemistry didn’t make sense.

Dmitri Mendeleev Father of the Periodic Table WHAT HE DID… SOME PROBLEMS… ● Put elements in rows ● He left blank spaces for by increasing atomic weight what he said were undiscovered elements. ● Put elements in columns by the way they reacted. ● He broke some patterns

● A: Atomic number = ● ● number of protons B: The elements charge C: The elements symbol D: The name of the element E: Atomic Mass or the number of protons and neutrons

● Atomic number - # of protons ● Atomic Mass – Mass of protons and neutrons ● So… how do you calculate the number of neutrons? Atomic Mass – Atomic number = # of neutrons! ● Number of Electrons equals the number of protons in a neutral atom.

● P. 94 -97 # 1, 3, 6, 7, 11 -21