Chp.1 & Chp.2: Classification of Matter, Atoms, and Molecules

Flashcards covering the classification of matter, atomic structure, isotopes, and chemical compounds (ionic and covalent) based on the lecture notes from Chapters 1 and 2.

Matter

Anything that has mass and volume.

Pure Substances

Matter that is uniform throughout and cannot be separated by physical means.

Mixture

Two or more pure substances physically combined.

Heterogeneous Mixture

A mixture that is not the same throughout.

Homogeneous Mixture (Solution)

A mixture that is the same throughout.

Elements

A pure substance consisting of a single type of atom.

Compounds

A pure substance that is the chemical combination of two or more elements.

Solid

A state of matter with definite volume and definite shape.

Liquid

A state of matter with definite volume and indefinite shape.

Gas

A state of matter with indefinite volume and indefinite shape.

Physical Properties

Can be measured or observed without changing the composition or identity of the substance (ex: density, color, melting point).

Chemical Properties

Describe the way a substance may change or react to form other substances (ex: flammability, corrosivity).

Chemical reactions

Occur during chemical changes, altering the identity of a substance.

Electron

A subatomic particle with a mass of 9.10939 x 10^-28 g and a charge unit of -1.

Proton

A subatomic particle with a mass of 1.67262 x 10^-24 g and a charge unit of +1.

Neutron

A subatomic particle with a mass of 1.67493 x 10^-24 g and a neutral charge (0).

Atomic Number (Z)

The number of protons (p+) in an atom. In a neutral atom, it also equals the number of electrons (e-).

Mass Number (A)

The total number of protons and neutrons in an atom (A = p+ + n0).

Ions

Atoms that have lost or gained electrons, resulting in a net electrical charge.

Cations

Positive ions, usually formed by metals when they lose electrons.

Anions

Negative ions, usually formed by non-metals when they gain electrons.

Polyatomic ions

Ions consisting of two or more atoms chemically bonded together (e.g., NH4+, SO4^2-).

Isotopes

Atoms of the same element (same atomic number) that have different numbers of neutrons (different mass numbers).

Atomic Mass Unit (amu)

A unit of mass previously defined as 1/12 of the weight of a 12C atom, equal to 1.661 x 10^-24 g.

Mass Spectrometry

A method used to separate ionized isotopes due to differences in their mass-to-charge ratio and calculate their relative abundances.

Atomic Mass

The weighted average of the masses of all naturally occurring isotopes of an element, expressed in amu.

Carbon-14 (C-14)

A radioactive isotope of carbon used in radiocarbon dating, with a half-life of 5730 years.

Metals

Elements typically found on the left and center of the periodic table, generally characterized by luster, malleability, ductility, and high conductivity.

Non-metals

Elements typically found on the upper right side of the periodic table, generally appearing dull, brittle, and acting as poor conductors.

Metalloids

Elements located along the diagonal line between metals and non-metals on the periodic table, exhibiting properties of both.

Periods

Horizontal rows in the periodic table, where elements are arranged in order of increasing atomic number.

Groups (Families)

Vertical columns in the periodic table, where elements have similar chemical properties.

Alkali metals

Elements in Group 1A (Li, Na, K, Rb, Cs, Fr) of the periodic table, known for their high reactivity.

Alkaline earth metals

Elements in Group 2A (Be, Mg, Ca, Sr, Ba, Ra) of the periodic table, also highly reactive.

Chalcogens

Elements in Group 6A (O, S, Se, Te, Po) of the periodic table.

Halogens

Elements in Group 7A (F, Cl, Br, I, At) of the periodic table, known for forming salts.

Noble gases (or rare gases)

Elements in Group 8A (He, Ne, Ar, Kr, Xe, Rn) of the periodic table, characterized by their inertness or low reactivity.

Chemical compounds

Substances formed from fixed ratios of atoms or ions.

Ionic Compounds

Compounds formed between cations and anions, typically involving the transfer of electrons from a metal to a non-metal.

Covalent Compounds

Compounds formed between nonmetal atoms, where electrons are shared.

Empirical Formula

The simplest whole-number ratio of atoms of each element in a compound. Ionic compounds always have empirical formulas.

Molecular Formula

The exact number of atoms of each element in an individual molecule. Covalent compounds typically have molecular formulas.

Structural Formula

A chemical formula that shows the exact connectivity of the atoms in a molecule.

Molecule

An aggregate of at least two atoms in a definite arrangement held together by covalent chemical bonds.

Covalent bond

A chemical bond in which electrons are shared between non-metal atoms.

Diatomic Elements

Seven elements (H, N, O, F, Cl, Br, I) that occur naturally as molecules containing two atoms.

Acid

Hydrogen-containing covalently bonded compounds that give off H+ ions when dissolved in water.

Inorganic compounds (covalent)

Covalent compounds typically formed between two non-metals, not primarily composed of carbon and hydrogen.

Organic compounds

Covalent compounds that primarily contain carbon and hydrogen (hydrocarbons) and their derivatives.

Alkane

A type of organic compound (hydrocarbon) characterized by only single bonds between carbon atoms (e.g., Ethane).

Alkene

A type of organic compound (hydrocarbon) characterized by at least one double bond between carbon atoms (e.g., Ethylene).

Alkyne

A type of organic compound (hydrocarbon) characterized by at least one triple bond between carbon atoms (e.g., Acetylene).

Aromatic compound

A type of organic compound characterized by cyclic structures with delocalized pi electrons (e.g., Benzene).

Polymer

Large molecules formed from repeating structural units (monomers), often derived from organic compounds (e.g., Polyethylene).