Chapter 5: Chemicals and Their Properties - Summary Notes

Pure substances are classifiable by their properties.
Changes are classifiable as chemical or physical.
A substance’s properties (chemical & physical) determine its usefulness and effects.
Ionic compounds consist of positive and negative ions.
Molecular compounds consist of distinct molecules.
Many consumer products are developed from petrochemicals.

A space elevator would consist of a long cable attached to Earth’s equator with a large mass at the other end (40,000 km up).
The mass would orbit Earth at the same rate as Earth rotates, keeping the cable taut.
A "space-proof" elevator car could climb the cable.
Questions needing answers:
- Cable requirements and operating conditions.
- Physical and chemical properties of the cable.
- Suitable common substances and their limitations.
- Potential modifications to overcome limitations.
- Impact on our lives and planetary home.

Hyponatremia: A condition of disorientation and loss of balance caused by drinking too much water, resulting in diluted sodium concentration in the blood.
An atom is an electrically neutral particle with equal electrons and protons.
An ion is a charged atom due to gaining or losing electrons.
Sodium atoms lose one electron to form $Na^+$ ions (positive charge).
Fluorine gains an electron to form $F^-$ ions (negative charge).
Noble gases are stable due to full outer orbits.
Sodium and fluoride ions are stable because they have the same electron arrangement as neon.
Sodium loses its outermost electron to achieve a stable electron arrangement like neon.
Fluorine gains an electron to achieve a stable electron arrangement like neon.

Chemistry: Study of substances, their composition, behavior, and uses.
Physical Property: A characteristic or description of a substance (e.g., color, texture, density, smell, solubility, taste, melting point, physical state).
Chemical Property: A characteristic behavior when a substance changes into a new substance (e.g., flammability, bleaching ability, corrosion).
Physical Change: Does not produce a new substance (e.g., changes of state, dissolving).
Chemical Change: Produces a new substance (or more than one new substance).
Evidence of Chemical Changes:
- A new color appears.
- A solid material (precipitate) forms in a liquid.
- Heat or light is produced or absorbed.
- Change is generally difficult to reverse.
- Bubbles of gas are formed.

WHMIS (Workplace Hazardous Materials Information System): Provides information on the safe use of hazardous products in Canadian workplaces.
WHMIS Information is conveyed through:
- Product labels.
- Materials safety data sheets (MSDS).
- Worker training.
Supplier Label: Required on hazardous materials sold or imported to a workplace in Canada; includes hatched border, bilingual (English/French), product name, hazard symbol, supplier information, and MSDS reference.
Workplace Label: Required on hazardous materials produced or transferred within a workplace; includes product name, safe handling information, MSDS reference, and hazard symbol.
MSDS (Materials Safety Data Sheet): Provides detailed information on hazardous properties, safe handling/storage, and emergency procedures.

Element: A pure substance that cannot be broken down into simpler substances.
Periodic Table: Used to explain and predict element properties.
Metals: Generally solid, shiny, malleable, and conductors of electricity.
Non-metals: Solid, liquid, or gas; dull, brittle (if solid), and insulators.
Period: Each row of elements in the periodic table.
Group: Each column of elements with similar properties.
Alkali Metals: Group 1 elements (except hydrogen); soft, highly reactive metals.
Alkaline Earth Metals: Group 2 elements; light, reactive metals.
Halogens: Group 17 elements; one of the most reactive groups.
Noble Gases: Group 18 elements; stable, rarely react.
Atomic Structure:
- Proton ( $p^+$ ): positive charge, located in the nucleus.
- Neutron ( $n^0$ ): neutral charge, located in the nucleus.
- Electron ( $e^−$ ): negative charge, orbits around the nucleus.
- Atomic Number: Number of protons in the nucleus; elements arranged in order of increasing atomic number.
Bohr−Rutherford Diagram: Represents arrangement of electrons around the nucleus.
- First orbit holds up to 2 electrons.
- Second and third orbits hold up to 8 electrons each.

Ion: Atom that has become charged by gaining or losing electrons.
Sodium Ion ( $Na^+$ ): Sodium atom loses one electron; has +1 charge.
Fluoride Ion ( $F^−$ ): Fluorine atom gains one electron; has -1 charge.
Noble Gases: Stable due to full outer orbits.
Sodium and Fluoride Ions: Stable because they have the same electron arrangement as neon.
Aluminum: Can lose 3 electrons to form $Al^{3+}$ ions.
Sulfur: Gains 2 electrons to form $S^{2−}$ ions.
Cation: Positively charged ion.
Anion: Negatively charged ion.

Ionic Compound: Compound made up of positive (metal) and negative (non-metal) ions(e.g., sodium chloride - table salt)
Ionic Bond: Attraction that holds oppositely charged ions together.
Ions join together to form an ionic crystal.
When dissolved in water, water molecules surround each ion, preventing them from rejoining the crystal.
Electrolyte: Compound that separates into ions when dissolved in water, producing a solution that conducts electricity.

IUPAC (International Union of Pure and Applied Chemistry) is the organization that decides how chemicals will be named.
The name of the metal ion remains the same as the name of the neutral metal atom, but the ending of the name of the second ion- the nonmetal- changes to "ide".
The compound's total ion charge- the negative and positive ion charges added together- must equal zero.
If there are two charges on the copper ion, use x to represent the unknown value. Remember that the charge on all the ions must remain zero overall.

Polyatomic Ion: Ion made up of more than one atom that acts as a single particle (e.g., phosphate $(PO_4)^{3-}$ .
The ionic charge of a polyatomic ion is shared over the entire ion rather than being on just one atom.

Molecular Compound: Pure substance formed from two or more non-metals.
Molecule: Individual particle in a molecular compound.
Chemical Formula: Gives exact numbers of atoms in each molecule.
Covalent Bond: Bond resulting from sharing outer electrons between non-metal atoms.
Diatomic Molecules: Molecules consisting of two atoms joined with a covalent bond.
Molecular Compounds: Naming involves using prefi xes to specify the number of atoms.