Final Flashcards
Law of multiple proportions
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 simple integer ratio
Law of definite proportions
When two or more elements combine to form a compound, their masses in that compound are in a fixed and definite ratio
Which law proves atoms, and how?
LOMP- integer ratios by mass are observed meaning there cannot simply be any amount of that element. There are a few specific masses which will combine w/ the other element. The simplest explanation for these integers is that elements exist as fixed units of mass, or particles.
Atomic molecular theory
1) each element is composed of very small, identical particles called atoms
2) all atoms of a single element have the same characteristic mass
3) the number and masses of these atoms do not change during chemical transformation
4) each compound exists of identical molecules, which are small, identical particles formed of atoms combined in simple whole number ratios
Law of Combining Volumes
When gases combine during a chemical reaction at fixed T and P, the volumes of the reacting gases and products are in simple integer ratios
Which two laws prove Avogadro’s Hypothesis?
LOCV and AMT- assume the integer ratios seen in ATM w/ LOMP must be the same integers observed in the LOCV. So LOCV integers must be counting particles in the gas in the same way that ATM counts atoms in compounds.
Avogadro’s Hypothesis
Equal volumes of gas at fixed T and P contain equal numbers of particles
How to prove Avogadro’s Hypothesis?
Assume its not true, if gases contained different numbers of particles for the same volume, then for the particles to react in integer ratios as seen by the LODP, it would take non integer volumes of gas, violating the LOCV which is experimentally observed.
What proves diatomics?
Avogadro’s hypothesis
What laws allow us to count atoms and find molecular formulas?
LOCV and Avogadro’s Hypothesis
What were the three observations of Rutherford’s experiment?
1) most particles passed straight through
2) smaller number were deflected at an angle
3) even fewer were deflected straight back
What are the three conclusions of Rutherford’s?
1) atoms are mostly empty space
2) the nucleus must be positively charged
3) most of the mass of the atom must be concentrated in a very small fraction of the volume of the atom (nucleus)
What did the X-ray emission experiment prove?
It proved that atomic number was a physical property of the atom as well. Atomic number must have accounted for the number of electrons and protons in an atom.
Coulombs Law
Relates the strength of the interaction between two charged particles to the sizes of the charges on the particles and the distance between them
More negative PE?
= higher IE= stronger attraction
Less negative PE?
= Smaller IE= less attraction
Periodic Law
The chemical and physical properties of the elements are periodic functions of the atomic number
Ionization energy
The amount of energy required to remove an electron from an atom
Which proves electron shells?
IE graph with periodic law form and the successive IE chart,
Also hydrogen spectrum with photoelectric effect.
What is the equation for core charge?
Core charge = nuclear charge - # core electrons
Which experiment proves photons? How?
Photoelectric effect. Shows that very little high frequency light can accomplish what an enormous amount of low frequency light cannot. Light must therefore be quantized into packets (photons) that act individually on a target.
What are the 3 conclusions of the photoelectric effect graphs?
1) energy is proportional to frequency
2) energy is in packets called photons
3) intensity is proportional to photons
Why are 2s electrons lower in energy than 2p electrons?
Less e-e repulsion and more core penetration which incr eff nuclear charge
How do bond length and strength differ in single, double, triple bonds?
Bond strength = triple > double > single
Bond length = triple < double < single
