Exam 1 Flashcards
Elements
One atom type
Compounds
Made of 2 or more DIFFERENT elements chemically combined (H20, CL)
Molecule
Group of atoms or elements bonded together as a unit (H20, CO, O2)
1 Mg = 10 raised to…
6
1 Kg= 10 raised to
3
1 mg= 10 raised to
-3
1 microg= 10 raised to
-6
1 centi = 10 raised to
-2
Mass
Amount of matter in an object. Doesn’t change (dxv)
Weight
Gravitational force on the matter in an object
Density
Amount of matter in a given amount of space (m/v)
If ab object has less density does it go up or down?
Up (just like ice-cubes do on water)
Energy
The ability to do work or transfer heat
Potential energy
Stored energy (water at the top of waterfall)
Kinetic energy
energy in motion (water falling down)
Heat
energy that is transferred from hotter objects to cooler objects
Temperature
Average kinetic energy of the atoms or molecules that make up an object.
Formula to get K from C
C+273
Formula to get C from K
K-273
Law of conservation of mass
During a chemical change, the matter is neither created nor destroyed.
Law of definite proportions
A compound always contains the same elements in certain definite proportions. (H20 is always 2 hydrogen molecules with 1 oxygen molecule)
Law of Multiple Proportions
Elements may combine in more than one set of proportions with each set corresponding to a different compound.
The atomic theory of matter
- All matter is composed of atoms
- All atoms of a given element are alike and differ from the atoms of any other element
- Compounds are formed when atoms of different elements combine in fixed proportions
Isotopes
Atoms of the same element with different relative masses. (C-11, C-12). John Dalton’s atomic theory has been modified.
Not all elements are alike
Alessandro Volta
Electrochemical cell-battery
Humphry Davy
Used battery to produce Mg, Ca, Na, etc. to pass electricity thru molten (melted) salts.
Michael Faraday
Used battery and electrolytes apparatus to conduct electricity thru ionized solution.
Anode
Positive electrode
Cathode
Negative electrode
Electrolyte
A compound that conducts electricity when molten or dissolved in water.
Electrodes
Carbon rods or metallic strips that carry electrical current
Ion
An atom or group of atoms with a charge
Anion
Negative ion
Cation
Positive ion
Crooke
Invented Cathode Ray tubes to determine the charge to mass ratio of cathode rays
Thompson
Discovered electrons
Goldstern
Positive Particles
Roentgen
Discovered X-Rays
Becquerel
Discovered radioactivity
Robert MIlikon
Determined the charge of an electron and therefore the mass of an electron (oil-drop experiment)
Types of radioactivity
Alpha, Beta, Gamma
Alpha mass and charge
4 and 2+
Beta mass and charge
1/1837 and 1-
Gamma mass and charge
0 and 0
Rutherford Goil
Foil Experiment (Placement of atom charges) Used radioactive alpha particles. Positive charges occupies only tiny fraction of volume of an atom negative charged electrons are outside the nucleus. Electrons occupy almost all volume of an atom
Subatomic Particles
Proton, neutron and electron
Proton mass, charge and location
1, 1+ and nucleus
Neutron mass, charge and location
1, 0 and nucleus
Electron mass, charge and location
1/1837, 1- and outside the nucleus
Atomic numbers
the number of protons in a nucleus
Mass number
Sum of protons and neutrons in a nucleus
Isotopes can have…
the same atomic number but have different mass numbers (= protons, different neutrons)
neutral element
protons=#electrons
How to get # of neutrons
Subtract atomic number (z, or protons) from mass number (A)
How to get mass number?
Top number Z
The Bohr Model
Flame tests
Different elements give different colors to a flame
Continous spectra
when light emitted from a solid substance is passed thru a prism, it produces colors.
Quantum
A tiny unit of energy produced or absorbed when an electron makes a transition from one energy level to another
Ground state
When electrons are in the lowest energy state
Excited State
when energy from a flame or other source is absorbed by the electrons they are promoted to a higher state
Photon
When energy returns to a lower state, it emits a photon of energy which may be observed as light.
Energy states or shells max
1—2
2–8
3–8
4–2
Groups of periodic table
Vertical columns (families) have similar chemical properties. Have the same # of valence electrons
Periods of periodic table
Horizontal rows. Range of properties from metallic to nonmetallic. Tells you how many shells are in that atom
Valence electron
Electrons on the outermost shell
Group 1 has 1 valence electron
Group 2 has 2 valence electrons
Group 3 has 3 valence electrons
Group 1 name
Alkaline metals
Group 2 name
Alkaline earth metals
Halogens
Group 7 A
Noble Gas
Group 8A
Metals
First 2 groups. Conduct heat & electricity, malleable & ductile
Nonmetals
Dull luster, nonconductor, brittle in the solid state
Metalloids
Demonstrate properties of both metals & nonmetals
