chemical change 4-6

*negative *left of the staircase *Good conductors

*positive *right of the staircase *poor conductors *may be solid, liquid, or gas at room temp

• 1 valence electron • very reactive

• 2 valence elctrons *less reactive

*7 valence eletrons *very reactive *missing one electron in the valence

*unreactive *don’t bond with other elements *are stable because their valence is full

• vertical columns • used to determine how many electrons are in the valence

*horizontal rows *used to determine how many shells an atom has

The electrons in the outer shell of an atom

*atoms that share electrons *when 2 or more non-metals bond together

molecules made up of the same elements STRONG BONDS

1 - mono 2- di 3- tri 4- tetra 5- penta 6-hexa 7-hepta 8-octa

compounds made from 2 elements

*positively charged ions *METALS LOSE ELECTRONS

*Negatively charged ions *NON-METALS GAIN ELECTRONS

*have properties of both metals and non-metals *solid at room temp *poor conductors *brittle *not ductile

He proposed the law that when elements are organized in order of increasing atomic mass, there is repetition of properties

fluorine, chlorine, bromine

lithium, sodium, potassium

They are stored in oil to prevent oxidation and contact with moisture

similarities *Both occupy opposite sides of the chart *low densities Differences *Noble gases are very unreactive -alkali metals are reactive *noble gases are non-metals - alkali metals

ionic- uses both metals and non-metals, no prefixes molecular-only non-metals, uses prefixes

The substances that go into the chemical reactions

The substance produced by a chemical