Science Exam Review
CHEMISTRY
==alkali metals== are the most reactive elements and have 1 valence electron
==alkaline earth metals== are less reactive and have 2 valence electrons
==Halogen gases== are very reactive and have 7 valence electrons
==Noble gases== are not reactive and have a full valence shell (8)
==Ionic Compound:== metal + non-metal (cations + anions); The electrons transfer from the metal to the non-metal
==Molecular Compound:== non-metal + non-metal; the valence electrons are shared between the elements.
==Balancing equations==
coefficient multiplies by the subscript
balance metals first, then non-metals, then hydrogen and oxygen that are in compounds, then stand-alone hydrogen and oxygen.
| ==Acids== | ==Bases== |
|---|---|
| - pH below 7- sour- corrosive to metals | - pH above 7- bitter- corrosive but not to metals- slippery |
the reactants of neutralization are acids and bases
the products of neutralization are salt and water
Synthesis: 2 elements combine to make a compound. (A+B → AB)
Decomposition: a compound breaks into smaller elements (AB → A+B)
Combustion: hydrocarbon combines with oxygen to produce carbon dioxide and water
Single Displacement: compound + element = element switches with an element in the compound (AB + C → CB + A)
if the single element is a metal it switches with the metal and vice versa.
Double displacement: a compound combines with another compound and the metals switch (AB + CD → CB + AD)
PHYSICS
types of light
| Incandescent | metal heats ups and glows which emits light |
|---|---|
| Fluorescent | light emitted when exposed to radiation |
| Phosphorescent | Gets light from other sources and releases it over time |
| Chemiluminescent | chemical reaction forms a light |
| Triboluminescence | friction causes light |
| Bioluminescence | organisms that produce their own light |
| Electric discharge | current passing through a gas |
when light travels from a faster medium to a slower one, it bends toward the normal
Lenses thicken when looking at things close
Lenses thin when looking at things farther
Near-Sighted: Image projects in front of the retina's concave/diverging lenses fix this
Far-Sighted: Image projects behind the retina, convex/converging lenses fix this