Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
all matter can be broken down into __
|
elements
|
|
|
# of elements, # of natural elements
|
114, 88
|
|
|
3 facts known by chemists in the 18th century
|
1. materials were mixtures of pure substances
2. pure substances are elements or compounds 3. law of constant composition |
|
|
dalton's atomic theory
|
1. elements made of atoms
2. atoms in an element are identical 3. atoms of different elements are different from each other 4. compounds always have the same relative #s and types of atoms 5. atoms cant be divided in a chemical process |
|
|
compound is a...
|
distinct substance composed of atoms of two or more elements
relative mass is always the same |
|
|
chemical formula is..
|
notation for describing the type and number of atoms in a unit (molecule) of a given compound
|
|
|
rules for writing a chemical formula
|
1. each atoms is represented by a chemical symbol
2. the number of each type of atom is indicated by a subscript 3. 1 atom present means 1 subscript |
|
|
H2o (ex.)
|
a molecule consisting of 2 hydrogen atoms for every 1 oxygen atom
|
|
|
SO3
|
a molecule with 1 sulfur atom for every three oxygen atoms
|
|
|
atom is composed of 3 particles...
|
electrons
protons neutrons |
|
|
who discovered the electron
|
JJ Thompson
|
|
|
who proposed the plum pudding model
|
William Thompson
|
|
|
who discovered the proton
|
Ernest Rutherford
|
|
|
what did the discovery of the proton do
|
disproved the plum pudding model
led to the development of the nuclear atom |
|
|
who discovered the neutron
|
James Chadwick
|
|
|
what does the atom look like and composed of
|
positively charged nucleus surrounded by negatively charged electrons
nucleus (+) electrons (-) |
|
|
what does the nucleus look like
|
has positively charged protons
electrically charged neutral neutrons protons (+) neutrons (neutral) |
|
|
how big is the necleus
|
.00000000001 cm. (diameter)
10^-13 |
|
|
how is the atom charged electrically
|
neutral
number of protons and electrons are the same |
|
|
where is the mass of an atom contained
|
necleus
|
|
|
electron (relative mass and relative charge)
|
relative mass 1
relative charge (-1) |
|
|
proton (relative mass and relative charge)
|
relative mass 1836
relative charge +1 |
|
|
neutron (relative mass and relative charge)
|
relative mass 1839
relative charge none |
|
|
isotope
|
atoms with same number of protons but different number of neutrons
|
|
|
atomic number
|
number of protons in the nucleus
Z |
|
|
mass number
|
sum of the number of protons and the number of neutrons in the nucleus
A |
|
|
notation for an isotope
|
A
X Z (mass number) chemical symbol (atomic number) |
|
|
periodic table first arranged by
|
Dmitri Mendeleev
|
|
|
metals have physical properties like...
|
1. good conductor of heat and electricity
2. malleability (hammered into thin sheets) 3. ductility (can be pulled into wires) 4. a lustrous apperance (shiny) |
|
|
noble metals (unreactive)
|
Gold
Silver Platinum |
|
|
diatomic molecules
|
made up of 2 atoms of the elements
ex. O2 (oxygen gas) N2 (nitrogen gas) H2 (hydrogen gas) |
