Important Chemistry Formulas

Mass

The total number of protons and neutrons in an atom.

Average atomic mass

Calculated using the formula: (% abundance * atomic mass of isotope) + (% abundance * atomic mass of isotope).

Density

The mass of an object divided by its volume, represented as density = mass/volume.

Percent error

A measure of how inaccurate a measurement is; calculated as |Measured value - Accepted value| / Accepted value * 100.

Half-life

The time required for half of the original mass of a substance to decay.

m2

The mass remaining after a certain time period has elapsed in the context of half-life calculations.

m1

The original mass of a substance before decay.

t2

The time elapsed during the decay process.

t1

The half-life of the substance.

Half life formula

m₂= m₁(1/2)^(t₂/t₁)

How many orbitals and electrons are in the s, p, d, and f regions?

s: 1 orbital, 2 electrons.
p: 3 orbitals, 6 electrons.
d: 5 orbitals, 10 electrons.
f: 7 orbitals, 14 electrons.