General Chemistry: Subatomic Particles, Measurement, and Properties of Matter Vocabulary

Vocabulary flashcards covering atomic structure, mass spectrometry, metric prefixes, scientific notation, significant figures, measurement accuracy and precision, and properties of matter based on lecture notes.

Proton ($p^+$)

A subatomic particle located in the nucleus with a relative charge of $+1$ and relative mass of $1\,\text{amu}$ that determines elemental identity (Atomic Number $Z$).

Neutron ($n^0$)

A subatomic particle located in the nucleus with a relative charge of $0$ and relative mass of $1\,\text{amu}$ that provides nuclear stability, prevents proton-proton repulsion, and defines isotopes.

Electron ($e^-$)

A subatomic particle located in the electron cloud with a relative charge of $-1$ and relative mass of $\sim \frac{1}{1840} \approx 0\,\text{amu}$ that is responsible for chemical reactivity, bonding, and charge formation.

Subatomic Particles Summary

A reference table outlining the relative charge, relative mass in amu, location, and primary purpose/role of protons, neutrons, and electrons.

Atomic Number ($Z$)

The total number of protons in an atom, which defines the element.

Mass Number ($A$)

The whole number sum of protons and neutrons ($A = p^+ + n^0$), which is not found directly on the periodic table.

Relative Abundance

The fractional or percentage presence of a specific isotope naturally occurring on Earth.

Atomic Weight (Average Atomic Mass)

The weighted average mass of all naturally occurring isotopes of an element, calculated using $\text{Atomic Mass} = \sum(\text{Isotope Mass} \times \text{Fractional Abundance})$.

Mass Spectrometry Analysis Axes

In mass spectrometry, the $x$-axis represents the mass-to-charge ratio ($m/z$), corresponding to the isotope mass, while the $y$-axis represents relative abundance (intensity percentage).

kilo- ($k$)

A standard metric prefix representing $10^3 = 1000$.

deci- ($d$)

A standard metric prefix representing $10^{-1} = 0.1$.

centi- ($c$)

A standard metric prefix representing $10^{-2} = 0.01$.

milli- ($m$)

A standard metric prefix representing $10^{-3} = 0.001$.

nano- ($n$)

A standard metric prefix representing $10^{-9} = 0.000000001$.

Scientific Notation

A representation format expressed as $N \times 10^a$, where $1 \le \vert{}N\vert{} < 10$ and $a$ is an integer.

Leading Zeros

Zeros preceding all non-zero digits that never count as significant figures (e.g., $0.0025$ has $2$ significant figures).

Captive Zeros

Zeros trapped between non-zero digits that always count as significant figures (e.g., $1008$ has $4$ significant figures).

Trailing Zeros

Zeros at the end of a number that count as significant figures only if a decimal point is explicitly present (e.g., $120.0$ has $4$ significant figures, while $120$ has $2$ significant figures).

Instrument Reading Protocol

The measurement procedure requiring the user to always estimate one digit beyond the smallest calibration mark (the smallest graduation) on a measuring device.

Accuracy

How close a measured value is to the true or accepted value.

Precision

How close repeated measurements are to one another (reproducibility).

Percent Error Formula

A mathematical formula measuring inaccuracy given by $\text{\% Error} = \left\vert{} \frac{\text{Experimental Value} - \text{Accepted Value}}{\text{Accepted Value}} \right\vert{} \times 100$.

Physical Property

A property observable without changing the chemical identity of the substance (e.g., color, melting point, density, conductivity).

Chemical Property

A property describing a substance's ability to undergo a specific chemical change (e.g., flammability, reactivity with acid, oxidation potential).

Intensive Property

A physical or chemical property independent of sample size or amount (e.g., density, temperature, concentration, boiling point).

Extensive Property

A property that depends on the sample size or amount present (e.g., mass, volume, total energy).

Density

The mass per unit volume of a substance, defined mathematically as $D = \frac{m}{V}$.