Unit 2 Review: Matter, Atomic Structure, and Nuclear Chemistry

Vocabulary flashcards covering unit 2 topics including physical and chemical properties, atomic structure, historical atomic models, isotopes, average atomic mass calculations, and nuclear reactions.

Chemical Properties and Changes

Properties and changes that describe a substance's ability to undergo a chemical reaction and transform into new substances, including flammability, toxicity, eating food, and potassium chlorate decomposing into potassium chloride and oxygen gas.

Physical Properties and Changes

Properties and changes that can be observed or measured without altering the chemical composition of matter, including volume, luster, length, mass, density, brittleness, ice melting, water absorbed by a towel, slicing sodium in two parts, and sugar dissolving in water.

Subatomic Particles

The constituent particles of an atom: protons with a positive charge of $+1$ and a mass of $1\,\text{amu}$, neutrons with a neutral charge of $0$ and a mass of $1\,\text{amu}$, and electrons with a negative charge of $-1$ and a mass of $0\,\text{amu}$.

Isotope

Atoms of the same element that have the same number of protons (same atomic number) but different numbers of neutrons, resulting in different mass numbers.

Chronological Order of Atomic Models

The historical development of atomic models from oldest to newest: Model D (Dalton's Solid Sphere), Model C (Thomson's Plum Pudding), Model A (Rutherford's Nuclear Model), Model B (Bohr's Planetary Model), and Model E (Quantum Mechanical / Electron Cloud Model).

Subatomic Particle Calculation Rules

For any nuclear symbol ${}_Z^A\text{X}^q$, the atomic number $Z = \text{protons}$, mass number $A = \text{protons} + \text{neutrons}$, neutrons $= A - Z$, and electrons $= \text{protons} - q$ (where $q$ is ion charge).

Boron-11 Isotope Composition

An isotope of boron represented as ${}_5^{11}\text{B}$, consisting of $5$ protons, $5$ electrons, and $6$ neutrons.

Cobalt-56 Isotope Composition

An isotope of cobalt represented as ${}_{27}^{56}\text{Co}$, consisting of $27$ protons, $27$ electrons, and $29$ neutrons.

Silicon-28 Isotope Composition

An isotope of silicon represented as ${}_{14}^{28}\text{Si}$, consisting of $14$ protons, $14$ electrons, and $14$ neutrons.

Average Atomic Mass of Neon

The weighted average mass calculated as $(0.9099 \times 20) + (0.0800 \times 21) + (0.0101 \times 22) = 20.1002\,\text{amu}$, based on $90.99\%$ Neon-20, $8.00\%$ Neon-21, and $1.01\%$ Neon-22.

Average Atomic Mass of Iron Sample

The weighted average mass calculated as $(0.80 \times 56) + (0.05 \times 55) + (0.15 \times 57) = 56.1\,\text{amu}$ for a 1000-atom sample containing 800 Iron-56 ($80\%$), 50 Iron-55 ($5\%$), and 150 Iron-57 ($15\%$).

Helium-4 and Lithium-6 Nuclear Fusion

A nuclear fusion reaction written as ${}_2^4\text{He} + {}_3^6\text{Li} \rightarrow {}_5^{10}\text{B}$, producing Boron-10 as the product element.

Alpha Decay of Thorium-235

A nuclear reaction written as ${}_{90}^{235}\text{Th} \rightarrow {}_{88}^{231}\text{Ra} + {}_2^4\text{He}$, where Thorium-235 emits an alpha particle to form Radium-231.

Beta Decay of Nitrogen-16

A nuclear reaction written as ${}_7^{16}\text{N} \rightarrow {}_8^{16}\text{O} + {}_{-1}^0\text{e}$, where Nitrogen-16 emits a beta particle to form Oxygen-16.

Parent Isotope in Decay Reaction ${}_Z^A\text{X} \rightarrow {}_{92}^{235}\text{U} + {}_2^4\text{He}$

An alpha decay reaction where the parent isotope ${}_Z^A\text{X}$ is Plutonium-239 (${}_{94}^{239}\text{Pu}$), determined by balancing mass number ($235 + 4 = 239$) and atomic number ($92 + 2 = 94$).