Chemistry Review: Atomic Structure, Isotopes, and Spectroscopy

A set of fill-in-the-blank flashcards covering key topics from the notes: chemical laws, nuclear model, atomic notation, neutrons/electrons, percent composition, sig figs, atomic mass units vs. g/mol, isotope averaging, and basic spectroscopy equations.

In a given compound, the mass ratios of the elements are always __.

constant

The law of multiple proportions states that when two elements form more than one compound, the masses of the second element that combine with a fixed mass of the first are in __-number ratios.

simple whole-number ratios

Compounds are formed when atoms of different elements combine in -number ratios.

small whole-number

In Rutherford's gold foil experiment, most alpha particles passed through with minimal deflection, but some were deflected due to the presence of a small, dense inside the atom.

nucleus

In atomic symbols, the first letter is and the second letter (if present) is .

capital; lowercase

Mass number is written as a to the upper left of the symbol.

superscript

Atomic number is written as a to the lower left of the symbol.

subscript

The number of neutrons N is calculated as .

A − Z

For an ion with charge x+, there are electrons than protons.

one fewer

To calculate percent composition, you sum the mass contributions and divide by .

100%

In multiplication or division, the result should have as many significant figures as the factor with the sig figs.

fewest

In addition or subtraction, the result should be rounded to the least precise place.

decimal

AMU is the unit for the mass of a atom, while g/mol is the unit for the mass per of atoms.

single; mole

The weighted average atomic mass is calculated using the formula Aavg = sum (fractioni × mass_i) for all isotopes.

sum of products of isotopic fractions and their masses

Gallium has isotopes Ga-69 and Ga-71 with abundances 60.11% and 39.89%; the weighted average mass is approximately amu.

69.72

Red fireworks emission is due to light with a wavelength around nm.

650

The speed of light is c ≈ × 10^8 m/s.

2.998

One nanometer equals meters.

1.0 × 10^-9

The relationship between wavelength and frequency is given by the equation (i.e., λ = c / f).

λ = c / f

For λ = 650 nm, the frequency f is approximately Hz.

4.61 × 10^14