Chapter 2 Flashcards
Who coined the term “Atom”
Democritus
Who argued against the existence of Atoms
Plato
Who reasoned that the appearance of new substances through chemical change involved rearrangement of parts too small to be sen
Galileo
Who used atomic concepts to explain physical phenomena
Sir Isaac Newton
What are the 4 pieces of Daltons theory.
- All matter consists of extremely small particles called atoms
- atoms cannot be converted into atoms of another element
- atoms of an element are identical in mass and properties and are different from other atoms
- Compounds result from the chemical combination of a specific ration of atoms
What is used to detec contours of an atoms.
Tunneling Electron Microscope
Who created the Tunneling electron microscope
Binnig and Rohrer
Who discovered the Electron via a Cathode RAy Tube Experiment
JJ Thompson
JJ Thomson said the particles of a cathode ray of two properties
- They travel in straight lines
2. They are independant of the composition of the material from which they originate
Which experiment determined the charge on an electon and who did it.
Oil Drop experiment. Millikan
Which experiment determined the charge to mass ration of an electron and who did it
Cathode Ray Tube with capacitors and a magnet by JJ Thomson
How was the mass of an elctron first calculated
The charge from Milikans experiment divided by the mass to charge ration from JJ thomsons experiment gave us the mass.
Which Model gave us the idea that an atom is made of postive and negative charge particles uniformly
Plum Pudding by JJ Thomson and Kelvin
Which experiment gave us the atomic model today and who performed it
Rutherfords Gold Foil Experiment in which some particles bounced backwards as if hit by an extrememly desnse object
What is Rutherfords Theory
- Most of the mass and all of its positive charge are contained inside the nucleus.
- Most of the volume is empty.
- There are many electrons outside the nucleues as there are potons and these make the nucleus neutral
What was missing from the atomic theory that rutherford initially put together
Neutrons
Who later discoverd the neutron
Rutherfor and JamesChadwick
Which is slightly heavier neutrons or protons
neutrons
How much smaller is the mass of an electron than a proton and neutron relative to their mass of 1
.00055 or 1/1836
Which devices can be used help see atoms
- Electron microscope
- Scanning electron microscope
- atomic froce microscopes
What is the atomic Number and its symbol
Number of protons (Z)
What is the atomic number in the periodic table?
The number above the element.
JJ Thomson proposed that atoms contain negatively charged _______ based on experiments with cathode ray tubes
Electrons
JJ Thompson theorized that atoms must carry enough ______ charge to neutralize the negative charge of the _______.
Positive, electrons
What did Daltons postulate explain as far as scientific laws?
- Law Conservation of Mass
- Law of Constant Composition
- Law of mUltiple proportions
Scientific Laws provide a _______, often in the form of a ________ of what the scientific community observesr to match reality.
conside statement, mathematical equation
What is the Mass Number?
Number of Protons + Neutrons
How many protons, neutrons and electron are in 12, 6 C
6 Protons, 6 neutrons and 6 electrons
How many protons, neutrons and electrons are in 23, 11 Na
11 Protons 23-11 = 12 neutrons, 11 electrons
Atoms with the same number of protons but a different number of neutrons are called what?
Isotopes
What is an isotope?
Atoms that have the same number of protons but different numbers of neutrons
What are the atomic masses in Amu of protons, neutrons and electrons?
Proton = 1 Neutron = 1 Electron = 1/1836 or .0005486
What is the atomic mass?
The weighted average of the common isotopes of an element with respect to the average amount found naturally
How do you calculate the atomic mass
Take the isotopes of an element and their percentages found naturally and multiply by the Mass of those substances. then average the totals.
What is an atomic mass?
1/12 the mass of Carbon atom.
Transfer of electrons between compounds forms what kind of bond.
ionic
Share of electrons forms what kind of bond?
covalent
What is the formula for Metals to lose electrons.
M -> M+ + e-
What is the formula for metals to gain electrons
X+e- ->X-
When metals lose ions what do they become
Cations
When non-metals gain ions what do they become
Anions
Metals and NonMetals form what type of ionic compounds?
Cations
Do non-metals form cations or anion
anions
What is the Law of Mass Coservation
total mass of a substance does not change durring a chemical reaction
What is the Law of Definite Composition
no mater the source a compound is composed of the same elements in the same parts by mass.
What is the law of multiple proportions
when two chemicals react they for fixed whole number ratios
What does the mass spectrometer provide
The isotopic mass and the relative abundance as a percentage of a substance.
Who is credited with developering the periodic table
Dimitri Mendeleev
Group 1A Elements are known as what?
Alkali metals
Group 2A Elements are known as what?
Alkaline Earth Metals
Group 7A elements are known as what?
Halogens
Group 8A elements are known as what?
Noble Gasses
How does an ionic bond form?
Electrons are given up by one element or molecule to another .
How does a covalent bond form?
Electrons are shared between compounds or molecules.
Define an ionic binary compound.
Compound composed of ions of two elements only. (NaCl)
What is a monatomic ion?
A cation or anion derived from a single atome (Na+, Mg+, O 2-, F-)
Describe coulombs Law.
The energy of attraction or repulsion between two particles is directly proportional to the product of the charges and inversely proportional to their distance between them.
Are ionic compounds neutral?
Yes because they contain equal number of electrons and protons
In an ionic bond to Metals gain or lose electrons
Lose
In an ionic bond to Non-Metals gain or lose electrons
Gain
Name the 7 diatomic molecules
H2, N2, O2, F2, Cl2, Br2, I2
Name the octatomic molecules
S8, Se8
Name the tetraatomic molecules
P4