Matter and Atomic Structure Study Guide

Comprehensive vocabulary flashcards covering matter classification, subatomic particles, atomic structure, and periodic trends from the Matter Part A Unit Study Guide.

Mixture

A combination of two or more substances that are combined physically, in which the proportions can vary, components retain their original properties, and physical methods can be used to separate them.

Compound

A pure substance formed when two or more elements are combined chemically in fixed proportions, causing the properties of the individual components to change (e.g., ammonia, $NH_3$).

Single Compound (Particle Representation)

Diagram III, which depicts a pure chemical substance consisting solely of identical molecules made of two different elements chemically bonded together.

Air

A gaseous mixture composed primarily of $78\%$ nitrogen and $21\%$ oxygen.

Atom

The smallest particle of matter that can still be identified as a specific chemical element.

Subatomic Particles of an Atom

The three primary constituent particles of an atom: protons, neutrons, and electrons.

Neutron

An uncharged subatomic particle located in the nucleus with a mass of $1\,\text{amu}$.

Electron

A negatively charged subatomic particle that orbits outside the nucleus and is electrically attracted to positively charged protons.

Proton

A positively charged subatomic particle located in the nucleus with a mass of $1\,\text{amu}$; its quantity equals the atomic number and identifies the element.

Mass Number

The total sum of protons and neutrons contained inside the nucleus of an atom.

Diatomic Nitrogen ($N_2$)

A molecule formed when two individual nitrogen atoms chemically bond together.

Particles Determining Net Electric Charge

Protons and electrons, whose balance of positive and negative charges determines the overall charge of an atom or ion.

Group (Periodic Table)

A vertical column of elements on the periodic table that share identical numbers of valence electrons and exhibit similar chemical properties.

Manganese Nucleus Particles

The $55$ total subatomic particles (nucleons) located in the nucleus of a manganese atom with an atomic number of $25$ and an atomic mass of $55\,\text{amu}$.

Metals

The chemical classification representing the majority of the elements on the periodic table, located predominantly to the left and center.

Hydrogen Atom Physical Model Inaccuracy

The relative mass of particles, since using equally sized balls (such as golf balls) fails to account for a proton being roughly $1836$ times heavier than an electron.

Hydrogen Ion ($H^+$)

A hydrogen atom that has lost its single electron, leaving behind a single proton and resulting in an overall electric charge of $+1$.

Element with the Least Protons (Periodic Table Diagram)

Element A (Sodium), which sits highest and furthest to the left (Period 3, Group 1) among the marked positions, giving it the lowest atomic number.

Product (Reaction: $2Ca + O_2 \rightarrow 2CaO$)

Calcium oxide ($CaO$), the chemical compound produced on the right-hand side of the reaction.

Chromium Nucleus Subatomic Particles

A total of $52$ nuclear particles, calculated by adding its $24$ protons and $28$ neutrons ($24 + 28 = 52$).

Group 2 Alkaline Earth Metals ($Be$, $Ca$, $Ra$)

The elements beryllium ($Be$), calcium ($Ca$), and radium ($Ra$), which display the most similar chemical behaviors because they share Group 2 on the periodic table.

Nitrogen Oxide Molecular Models A and C

Molecules composed of nitrogen and oxygen; Model A represents nitric oxide ($NO$) consisting of one nitrogen and one oxygen atom, while Model C represents nitrogen dioxide ($NO_2$) with one nitrogen atom bonded to two oxygen atoms.

Nuclear Comparison of Potassium ($K$) and Calcium ($Ca$)

Potassium (atomic number $19$, mass $39\,\text{amu}$) has one less proton than calcium (atomic number $20$, mass $40\,\text{amu}$), but both elements possess exactly $20$ neutrons.