Compounds November 9, th grade Chapter 3.2

Meme Moment

Scientist of the Day

Frederick Soddy Worked with Rutherford Discovered different types of radiation Nobel Prize in chemistry Started writing books about economics instead o People thought he was a crackpot, but his ideas are used today o Predicted that economy would run on fossil fuels instead of gold Was going to have an element named after him, but “Soddyium” sounds like sodium

Atoms Atom: Smallest unit of matter. o Except not really, because atoms are made up of ‘subatomic particles’ Substances made of one type of atom are called elements. There are only 118 known elements in the universe o You can see them all on the periodic table (which is a little out of date) o Each atom has a symbol. E.g. Oxygen is O. All of them (except hydrogen and helium) were made in stars

Molecules Molecule: 2 or more atoms stuck together to make a substance (chemical). The atoms are joined with chemical bonds Chemical bond: force of attraction between 2 atoms

Symbols for Molecules HBrO 4 Each atom has a symbol from the periodic table Symbols can be 1 or 2 letters. First = capital, second = lower case or none Numbers say how many No number = 1

Practice! How many/what type of atoms do these molecules have? H 2 O CuBr 2 HgCl 2 NaCl KNO 3