Which Science is primarily concerned with the study of matter and the changes it undergoes?
Natural Philosophy
theoretical speculatuon about nature
DDT- insecticide during WWII
Carsonian nightmare
Science is
tentative, explanatory, testable, predictive, reproducible
Proposing butadiene in glue will make it stickier is an example of a(n)
Results in an experiment are easier to interpret when the experiment has how many variables?
Synthesizing a medical remedy for cancer is an example of what kind of research?
Applied Research
Does the weight of a person change when there are gravitational differences?
Does the mass of a person change do to gravitational differences ?
A compound that conducts electricity when molten or dissolve in water
Carbon rods or metallic strips that carry electrical current
a positive electrode
a negative electrode
an atom or group of atoms with a charge
a negative ion
A positive ion
Leucippus and Democritus
Discovered that atoms cannot be subdivided and molecules are atoms chemically bonded together
Law of Conservation Mass: matter can neither be created nor destroyed
Law of Definite Proportions: compound always contains the same element in definite propoetions
Experiment to illustrate Law of Definite Proportions: Lead Sulfide
John Dalton
Law of multiple proportions: Different atoms can combine with different ratios
atoms of same element (atomic number)with different masses (atomic weight)
arranged elements in order of increasing atomic mass
J.J. Thomson
discovered electrons — cathode anode tube
used cathode ray tube– discovered xrays (electromagnetic radiation)
discovered radioactivity
Marie and Pierre Curie
worked to isolate pure radioactive substances
Types of Radioactivity
Alpha: Positive
Beta: Negative
Gamma: Neutral
gold foil experiment: discovered nucleus
Atomic #
the number of protons and electrons in the nucleus
Atomic Weight #
Sum of protons and neutrons in the nucleus
Same # of protons and electrons, different number of neutrons
Elements give different color flames
Flame Test
Light from gas substances pass through prism to produce a line– result from electrons returning to lower levels
Line Spectrum
When energy from a flame or source is absorved by the electrons and promoted to a higher energy state
Excited State
Ground State
when electrons are in the lowest stare of energy
When a tiny unit of energy is produced or absorved when an electron makes a transition from one energy level to another
When an electron in an excited state returns to a lower energy state, it emits ___ of energy which may be observed as light
observed positive rays using perforated cathode
Determined Charge of electrons by oil-drop experiment *calculated the absolute mass of an electron
Another name for Energy levels
The Quantum Model
What is the Quantim Model composed of?
principle energy levels,sublevels, and orbitals(1,2,3,4,5..)
Principle Energy Levels (shells)
roughly correlate to the distance that an electron is from an atom’s nucleus
each principle energy level (n) is divided into {s,p,d,f}
regions in space that represent a high probability of locating an electron
Electron Configuration
represents the arrangement of the electrons in an atom
What is the periodic table composed of?
Groups(families): vertical columns containing similar chemical properties
Periods: horizontal rows range of metallic to nonmetallic
Valence Electrons
-in the outermost principle energy level of an atom
-gained lost or shared in chemical reactions
-elements in a group or family have the same amount
What’s the major distinction b/w Greek Philosophers and Modern Scientists?
Scientific Results must be Verified by?
Further Experiment
Example of Basic Research
Otto Stern and Walther Gerlach’s discovery that atomic nuclei have spins
Mass is a better measure of the amound of matter than weight is because
Mass is Independent of location
Sodium reacts with water to form sodium hydroxide, this is an example of ?
Chemical Property
Chemical Change always involves a change in the ___ of a piece of matter?
Characteristics of Gas
Indefinite shape, indefinite volume
Substance that cannot be broken down by chemical means into simpler substances is called?
an Element
Freezing point for Celsius
0 degrees
The energy content in food is in Calories, Calorie is equal to__?
1000 calories
If 1 Calorie is equal to 1000 calories, how many Joules are there?
4.184 Joules
Leucippua and Democritua propoaed the “first” atomic vire of matter based on?
philosophical and intuitive speculation
Methane can be decomposed into simpler substaces, therefore?
it cannot be an element
the atomic masses for elements in the periodic table are ?
relative masses determined by comparison with a standard reference
a stream of electrons will behave in what way in an electrical field?
be deflected toward the positive electrode
the spontaneous emission of radiation from unstable elements
which type od radioactivity is NOT deflected by a magnetic field?
The nuclear model of the atom waa constructed from which fundamental experiment?
Alpha particles scattering by thin metal foils
Relative to the mass of the nucleus of an atom, the mass of the electron is?
always much smaller
the identity of an element is determined by what?
the number of protons in the atom
The MAX number of elextrons in the n=4 energy level is?
What is the max number of electrons that can occupy the 3p sublevel?
Elements in the same group have?
the same number of valence electrons
The inertness of the noble gases is due to?
the number and arrangement of their electrons
When atoms lose or gain electrons in chemical reactions they form
With reapect to chemical bonding, which particles play the most active role?
Valence Electrons
the attraction between positive and negatice ions is known as an
ionic bond
When sodium loses a valence electron its core electrons are configured like which noble gas?
Chlorine can gain an electron and its electron structure becomes like?
Octet Rule
In chemical reactions atoms tend to gain, lose or share electrons so as to have eight valence electrons.
Metals lose electrons to take on the electron structure of the previous noble gas. They form__?
Nonmetals tend to gain electrons to take on the electron structuee of the next noble gas. They form__?
Covalent Bond
sharing of electrons
Polyatomic ions
groups of covalently bonded atoms with a charge
How many rules are there for sketching Lewis Structures?
Rule #1
Count Valence Electrons
Rule #2
Sketch a skeletal structure
Rule #3
Place electrons as lone pairs around outwe atoms to fulfill the octet rule
Rule #4
Subtract the electrons used so far from the total number of valence electrons. Place any remaining electrons around the central atom.
Rule #5
If the central atom lacks an octet, move one or more lone pairs from an outer atom to a double or triple bond to complete an octet
Free Radicals
an atom or molecule with an unpaired electron
The Valence Shell Electron Pair Repulsion (VSEPR)
theory predicts the shape of molecules and polyatomic ions based on repulsions of electron pairs on central atoms
What must happen in order for a molecule to be polar?
1. it must have polar bonds
2. the bonds must be arranged such that a separation of charge exists