Chemistry Chapter 4

atom

smallest particle of an element that retains chemical properties

protons

positive charge in nucleus

nuetron

nuetral charge

electron 

negative charge 

Democritus

atoms are indivisible

Aristotle

matter is continuous

law of conservation of mass

mass cannot be created nor destroyed

law of multiple proportions 

every sample of a particular chemical compund contains the same elements and exactly the same proportions by mass

law of multiple proportions

two elements combine to create two different compunds the ratio of the masses of one element combines with another is a small whole number 

John Dalton

all elements are made of atoms, discovered the elctron

cathode

the metal disk connectedto the end of the voltage source

anode

the metal disk connected to the positive end

Rutherford Gold Foil

alpha particles were sent through the gold foil

nucleus density

2×10^8 metic tons

Nuclear Theory 

atoms mass is charge in nucleus, volume is empty space, atom is nuetral 

proton mass

1.67262×10^-27

nuetron

1.672693×10^-27

electron

0.00091×10^-27kg

Proton 

the atoms identity 

Chemical symbol

Ag

periodic law

chemical and physical properties based on atomic #

periodic table

organized based on atomic # and properties

Cannizzaro

atomic mass

Mendeleev 

period table 

Moseley

organzizing table based on atomic #

valence electrons

outermost electrons want 8

ion

a chemical atom with a net charge

metals

lose electrons during a chem reaction, mostly solid, ex. mercury

non metals 

gain electrons during a chem reaction most are gasses, brittle 

metalloids

properities from both groups, room temp solids

chemical reactions

stability of atom

cation

atom loses electrons gains charge

anion

gain electron loses charge

isotopes

atoms with the same # of protons different # of neutrons

amu

based off of the carbon 12

overall charge of an atom

0

alkali metals

very reactive, react strongly with water, found in compounds 

alkaline earth metals 

reactive, not found in nature 

transitional metals

metals that are good conductors, vary in reactivity 

halogens

most reactive nonmentals, form salts

noble gases

all are unreactive

lanthanides

shiny metals, reactivity similar to akaline earth metals

actinides 

4 are found in nature, all are radioactive