CompoundsNovember 9, 2015

6th 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 insteado People thought he was a crackpot,

but his ideas are used todayo 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 universeo 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little out of date)o Each atom has a symbol.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

HBrO4

Each atom has a symbolfrom the periodic table Symbols can be 1 or 2 letters.

First = capital, second = lower case or none

Numbers say how manyNo number = 1

Practice!• How many/what type of atoms do these

molecules have?

• H2O

• CuBr2

• HgCl2• NaCl• KNO3