To Study Flashcards
Dalton’s model
-3 main conclusions
- elements are made of atoms
- atoms of an element are the same
- compounds are formed by combining atoms
Rutherford Experiment:
-what was involved?
-3 main conclusions
Involved bombarding gold foil with alpha particles. when some went through foil but others bounced off nucleus, discovered that…
- atoms are mostly empty space
- nucleus is positively charged
- nucleus is DENSE
Bohr model
-3 main conclusions
- electrons surround nucleus in ORBITS. farther from nucleus=more energy
- energy is ABSORBED when electrons to move to outer orbits energy
- energy is RELEASED (light) when electrons move back to ground state
3a. the light released is used to identify the element
Wave-mechanical model (modern)
- nucleus is small, dense, positively charged
- electron cloud surrounds nucleus
- orbitals are areas where an electron is LIKELY to be found
Charge and mass of proton neutron and electron
Proton:
1 amu
+1
Neutron:
1 amu
0
Electron:
0 amu
-1
An unstable nucleus means…
- ratio of protons to neutrons is not 1:1
- irregular ratio means not effective at holding nucleus together, becoming susceptible to radioactive decay: they will spontaneously decay and emit radiation
Nuclear fission and fusion
Fission: larger atom splits into 2 or more smaller, neutrons and energy are byproducts
*generates radioactive nuclear waste
Fusion: smaller atoms combine into one larger atom, energy is byproduct
Forms of spontaneous transmutation/natural decay
alpha and beta decay
What is ionizing and penetrating power? Which forms of decay have the highest and lowest of each?
Ionizing is the ability to damage molecules and DNA.
Highest: alpha
Lowest: Gamma
Penetrating is the ability to break through barriers.
Highest: gamma
Lowest: alpha
What are the results of gamma, alpha, and beta (minus and pos.) decay?
Alpha: mass decreases 4, atomic number decreases 2
Beta minus: atomic number increases 1
Beta pos: atomic number decreases 1
Gamma: everything stays the same, energy is emitted (photon)
***ON RT
Properties of ionic compounds
- HIGH melting and boiling points
- DO form crystals
- DO dissolve in water
- DO conduct electricity in a solution and as a liquid
Properties of covalent/molecular compounds
- LOWER melting and boiling points
- DO NOT form crystals
- INsoluble in water
- do NOT conduct electricity
OPPOSITE OF IONIC
How are metallic bonds formed?
valance electrons are mobile in a free moving “sea of electrons”
Combined gas law-relationship between…
-pressure and volume
-temperature and pressure
-temperature and volume
relationships between pressure, temp, and volume in sample of GAS
P and V: INVERSE
T and V: direct
T and P: direct
What is an ideal gas? When is a real gas most like an ideal gas?
Hypothetical gas model where molecules:
1. don’t repel or attract move in straight lines
2. move in straight lines with random motion
3. collisions result in transfer of energy but NO NET LOSS OF ENERGY
4. negligible volume
A real gas is most like an ideal gas when it’s at LOW temp and HIGH pressure
When will equal volumes of gas have an equal number of particles?
At the same temperature and pressure
potential and kinetic energy meaning? During a flat line what is happening to both? what about increasing line?
P: stored energy
flat line= (phase change) will increase
increasing line= stays the same
K: energy of motion
flat line=(phase change) will stay same
increasing line= increases
ONE CHANGES AT A TIME
Temp vs heat
Temperature: measures average kinetic energy, NOT form of energy
Heat: transfer of energy (usually thermal) from body of higher temp to lower
What is it called going from…
-gas to liquid
-liquid to gas
-liquid to solid
-solid to liquid
-gas to solid
-solid to gas
Gas to liquid: Condensation
Liquid to Gas: Vaporization
Liquid to Solid: Solidification (freezing)
Solid to liquid: Fusion (melting)
Gas to solid: deposition
Solid to gas: sublimation
When progressing across a period and down a group, what happens to:
-atomic radius
-metallic character
-electronegativity
-ionization energy
GROUP:
atomic radius INCREASES
metallic character INCREASES
electronegativity DECREASES
ionization energy DECREASES
PERIOD:
atomic radius DECREASES
metallic character DECREASES
electronegativity INCREASES
ionization energy INCREASES
elements in a different form but in the same phase will have ____properties and _____molecular/crystal structure.
Different properties and different structure
which types of solvent do ionic and covalent compounds dissolve in? (polar or nonpolar)
Ionic= polar
Covalent= nonpolar
How will adding a solute to a solvent affect freezing and boiling points?
HIGHER boiling point
LOWER freezing point