Chem 1&2

Mega (M)

10⁶

kilo (k)

10³

deci (d)

10^-1

centi (c)

10^-2

milli (m)

10^-3

micro (u)

10^-6

nano (n)

10^-9

pico (p)

10^-12

kelvin

c+273

Accuracy

the proximity of a measurement to the true value of a quantity

Precision

the proximity of several measurements to each other, regardless of how close to the true value

Addition & subtraction sigfig rule

answers are rounded to the least significant decimal place

Multiplication & division sigfig rule

answers are rounded to the number of digits that corresponds to the least number of significant figures in any of the numbers used in the calculation

Proton charge

positive

Neutron charge

neutral

Electron charge

negative

Proton & neutron mass

essentially the same

Electron mass

Ignored

Molecules

do NOT have to be two different atoms

Compound

HAVE to be two different atoms

Mass number

#of protons + neutrons

Atomic number

#of protons or electrons

Atomic number z

All atoms of the same element have the same number of protons

Isotopes

atoms of the same element with different masses (different #s of neutrons)

Average mass of isotopes

(mass₁*abundance₁)+(mass₂*abundance₂)

Ionic bonds

metal + nonmetal

Covalent bonds (molecular bonds)

nonmetal + nonmetal

Cation

a metal that loses electrons when reacted (has more protons than electrons)

Anion

a non-metal that gains electrons when reacted (has more electrons than protons)