ATOMS

Hypothesis

a reasonable and testable explanation for events

accuracy

how close a measurement is to the true value

precision

how closely several measurements of the same quantity made in the same way agree with
each other

chemical

any substance that has a definite composition

chemical reaction

a process that changes chemicals

matter

anything that has mass and volume

volume

the space an object occupies

mass

the quantity of matter contained in an object

weight

the force produced by gravity acting on a mass

protons

positively-charged, in the nucleus

neutrons

particles with zero charge, in the nucleus, help to stabilize the nucleus

electrons

negatively-charged, in the space around the nucleus

Quantum Numbers:

the address of the electron

energy level

the lower in energy level, the lower in energy, smaller in size, and closer to the nucleus

subshell

s, p, d, f (from lowest to highest energy; fills starting with lowest energy level)

orbital

s - 1 orientation (2 electrons maximum) sharp
p - 3 orientations (6 electrons maximum) principle
d - 5 orientations (10 electrons maximum) diffuse
f - 7 orientations (14 electrons maximum) fundamental

spin

orientation of the electron's magnetic field (either spin up or spin down)

kilo-

x 1000 (1 kilogram = 1000 grams)

centi-

x 0.01 (100 centimeters = 1 meter)

milli-

x 0.001 (1000 milliliters = 1 liter)

Dalton's Atomic Theory

1) All matter is composed of extremely small particles called atoms
2)Atoms of different elements combine in simple, whole-number ratios to form
compounds
3)In a chemical reaction, atoms are combined, separated, or rearranged, but never
created, destroyed, or changed.

Like changes..?

repel (two positive or two negative charges)

Opposite charges..?

attract (a positive charge to a negative charge)

In a neutral atom..?

the number of protons is equal to the number of electrons

physical property

a measurement of a material that does not change the identity of the molecule (examples: freezing point, size, density, mass, volume)

chemical property

a measurement of a material that changes the identity of the molecule (examples: reactivity, flammability)