Atomic Structure Unit Test Study Guide

Vocabulary flashcards covering atomic structure definitions, ions, isotopes, subatomic composition, and average atomic mass calculations.

Atom

The smallest particle of an element that retains the properties of that element.

Neutral Atom

An atom in which the number of protons ($+$) and electrons ($-$) are equal.

Electron Cloud

The area outside of the nucleus containing electrons.

Electrons

Negatively charged subatomic particles found outside of the nucleus.

Element Identity

Determined by the number of protons in an atom.

Neutrons

Subatomic particles found in the nucleus that carry no charge.

Atomic Number

Equal to the number of protons of an element, and the number of electrons in a neutral atom.

Mass Number

The total number of protons plus neutrons in an isotope.

One Atomic Mass Unit ($1\,\text{amu}$)

Equal to $\frac{1}{12}$ the mass of one atom of carbon-12.

Hyphen Notation

A notation style where the element name or symbol is followed by a hyphen and the mass number of the isotope.

Cation Formation

Occurs when electrons are lost, giving the ion more positive charges than negative, resulting in an overall positive charge.

Anion Formation

Occurs when electrons are gained, giving the ion more negative charges than positive, resulting in an overall negative charge.

Metal Ion Formation

Metals generally form cations by losing electrons.

Isotopes

Atoms of the same element that have the same number of protons, but different numbers of neutrons giving them different masses.

Composition of ${}_{30}^{65}\text{Zn}^{2+}$

$30\,\text{p}^+$, $35\,\text{n}^0$, $28\,\text{e}^-$

Composition of ${}_{95}^{243}\text{Am}^{6+}$

$95\,\text{p}^+$, $148\,\text{n}^0$, $89\,\text{e}^-$

Composition of ${}_{33}^{75}\text{As}^{3-}$

$33\,\text{p}^+$, $42\,\text{n}^0$, $36\,\text{e}^-$

Composition of ${}_{34}^{79}\text{Se}^{2-}$

$34\,\text{p}^+$, $45\,\text{n}^0$, $36\,\text{e}^-$

Chlorine Isotope Abundance

$\text{Cl-35}$ is most abundant because the average atomic mass is closer to $35$.

Average Atomic Mass Calculation (Iron Sample)

$$\text{AAM} = (55 \times 0.15) + (56 \times 0.85) = 55.85\,\text{amu}$$