Chem Flash cards

Daltons Atomic Theory of Matter

1. All matter is made up of atoms

2. All atoms that make up an element are identical in mass, size, and properties

JJ Thomson Cathode Ray Tube Experiment

Concluded atoms can be broken a part to something simpler (divisible)

Discovered the ELECTRON

Robert Millikan

Discovered CHARGE of electrons

conducted oil drop experiment to find the exact charge of an electron

JJ Thomson’s Plum Pudding Model of an Atom

discovered atoms are neutral so the surrounding is positive

Gold Foil Experiments

Experiment: shot tiny positive particles at a very thin sheet of gold.

Concluded: Discovery of the nucleus in atoms

The nucleus of an atom accounts for most of the atoms mass but very little of its size

Rutherford

Model of the Atom

conducted the gold foil experiment: nucleus is positive surrounded by revolving negative electrons

discovered the proton

Mass Spectrometry

Calculates the atomic weight of an element

Ionic compound

metal + nonmetal

molecular compound

nonmetal + nonmetal

Dmitri Mendeleev

created first periodic table

organized elements by mass then based on behavior

atomic theory

all matter is made of atoms

law of multiple proportions

comes from Daltons atomic theory

when two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in a ratio of small whole numbers

nuclide

A/Z X

fractional abundance

the ratio or decimal amount of a specific isotope found in a natural sample of an element

law of conservation of mass

mass can not be created nor destroyed

mass of reactants = mass of products

cation

positively charged ion

more protons than electrons

anion

negatively charged ion

atoms gain electrons

isotope

same number of protons but a different number of neutrons

Hypothesis

An untested explanation

what we think will happen but have not yet tested

Theory

an explanation that has been tested and verified

Law

A description that predicts what happens but does not explain how

Law of definite properties

samples of a given compound always contain the same proportion of elements by mass

molecular formula versus structural formula

A molecular formula shows the exact number of each type of atom in a molecule, while a structural formula shows how those atoms are connected and bonded together

molecule versus ionic compound

Ionic compound: transfer of electrons between metal + nonmetal

Molecular compound: sharing of electrons between nonmetal + nonmetal

Density

measure of how much mass is packed into a given space or volume

helpful for identifying a substance

helpful for determining if a substance is pure

Ex: fake gold is less dense than pure gold so density helps us identify fake gold

avogadros number

6.02 × 10^ 23

Alkai metals

group 1

alkaline earth metals

group 2

halogens

group 7A

noble gasses

group 8A

Charge for group 1

1+

Charge for Group 2

2+

Charge for Group 3A

3+

Charge for Group 4A

4+/-

Charge for Group 5A

3-

Charge for Group 6A

2-

CHarge for Group 7A

1-

Charge for Group 8A

0

write the following without scientific notation: 3.16 × 10^-5 m

31.6 um

convert to scientific notation: 2347.7

2.3 × 10³

convert to scientific notation: 0.2010

2.010 × 10^-1