Basic Science Information
Atomic Theory
· The atomic number – elements are listed in order of atomic number – represents the number of protons in that element
· Since the mass of any atom is made up of the nucleus (protons and neutrons) – the atomic mass represents the approximate number of protons and neutrons
o Zr – atomic number 40, mass number 91 means
91 - 40 = 51 neutrons
· Protons are positive, electrons are negative so they balance each other out
o Zr has 40 protons, and must have 40 electrons to remain neutral
· An atom of any element that has the same number of protons but a different number of neutrons is called an isotope.
· Isotopes can be stable or unstable (radioactive).
Density
· The weight of an object divided by the volume
o Different objects of the same size can have different weights
· Objects more dense than water will SINK.
· Objects less dense than water will FLOAT.
o This goes for objects within any substance – water, oil, or even air
Temperature
· The Celsius scale is based on the freezing and boiling point of water
o Boils at 100°C also 212°F
o Freezes at 0°C also 32°F
Visible light spectrum
· White light is made up of all the colors of the visible light spectrum
· ROYGBIV – Red, orange, yellow, green, blue, indigo, violet
· Electromagnetic spectrum contains visible light plus, l, b, g, X-rays, microwaves, radio waves, infrared and ultraviolet.
Area
· Area is calculated by multiplying length x width and is in units2
Volume
· Volume is calculated by multiplying – base x height x width and is in units3
· Can be measured in cubic centimeters (cc’s), equal to milliliters
Compounds
· Consist of 2 or more different elements
o Salt = one sodium atom Na and one chloride atom Cl or NaCl
o Water = two Hydrogen atoms H and one Oxygen atom O or H2O
o O2 – consists of 2 of the same element. This is not a compound
Unit Conversions
· Equivalence statements relate units to one another
o 100 centimeter = 1 meter
o 1,000 milliliters = 1 liter
o 1,000 meters = 1 kilometer
Phase Changes
· Sublimation – solid to gas change
· Evaporation – liquid to gas
· Condensation – gas to liquid
SI to English Unit Conversions
2.54 cm in 1 inch (distance)
0.95 l in 1 quart (volume)
453.6 g in 1 pound (weight)