Chemistry in Action - Science 20F

Comprehensive vocabulary flashcards reviewing subatomic particles, atomic structure, periodic table trends and families, chemical bonding, counting atoms, balancing equations, reaction classifications, and acid-base chemistry.

Atom

The smallest part of an element that still retains all the properties of that element.

Electron

A very tiny, light subatomic particle with a negative electrical charge ($-$) and the symbol $e^-$.

Proton

A subatomic particle that is much larger and heavier than an electron, carrying a positive electrical charge ($+$) and represented by the symbol $p^+$.

Neutron

A large and heavy subatomic particle with no electrical charge ($0$) and the symbol $n^0$.

Element

A pure substance whose atoms all have the same atomic number (the same number of protons in the nucleus).

Atomic Number

The fixed number of protons located in the nucleus of an atom that identifies each element.

Nucleus

The central core of an atom where all the mass of the atom is concentrated, containing protons and neutrons.

Ion

An atom that carries an electrical charge because it has gained or lost electrons.

Cation

A positively charged ion formed when an atom (usually a metal) loses electrons, causing the number of protons to exceed the number of electrons.

Anion

A negatively charged ion formed when an atom (usually a non-metal) gains electrons.

Bohr Model

A diagram used to represent an atom, displaying protons and neutrons in the nucleus and electrons arranged in surrounding orbits or energy levels.

Valence Electron Shell

The outermost electron shell or energy level that an element possesses.

Valence Electrons

The electrons located in the outermost electron shell that determine the chemical properties of an element and participate in bonding.

Lewis Dot Diagram

A shorthand diagram in which dots representing valence electrons are placed around the chemical symbol of an element.

Metals

Elements found on the left side of the zigzag line on the periodic table; most are shiny solids at room temperature, good electrical conductors, ductile, and malleable.

Ductile

The physical property of a metal that allows it to be stretched into thin wires.

Malleable

The physical property of a metal that allows it to be hammered or pressed out of shape without breaking or cracking.

Non-Metals

Elements found on the right side of the zigzag line on the periodic table; most are gases or brittle solids at room temperature and poor conductors of electricity.

Metalloids

Elements found near the zigzag line of the periodic table that possess properties of both metals and non-metals.

Families (Groups)

Vertical columns on the periodic table whose elements share common properties and possess the same number of valence electrons in tall columns.

Periods

Horizontal rows on the periodic table numbered $1$ to $7$, where the row number corresponds to the number of electron shells an atom has.

Alkali Metals

The Group 1A family of very reactive metals (especially with air and water) containing $1$ electron in their outer valence shell.

Alkaline Earth Metals

The Group 2A family of reactive metals containing $2$ electrons in their valence shell.

Chalcogens

The Group 6A family of non-metals containing $6$ electrons in their valence shell.

Halogens

The Group 7A family of non-metals that are the most reactive of the non-metals and contain $7$ electrons in their valence shell.

Noble Gases

The Group 8A non-metals that are gases at room temperature, do not react with other elements in nature, and have full valence shells ($8$ electrons, except Helium which has $2$).

Ionic Bond

A chemical bond formed between metals and non-metals when electrons are transferred, resulting in an electrostatic attraction between cations and anions.

Covalent Bond

A chemical bond formed between non-metals where atoms share electrons, consisting of at least $2$ shared electrons.

Diatomic Molecules

Molecules composed of two identical atoms bonded together because they are never found alone in nature ($I_2$, $H_2$, $N_2$, $Br_2$, $O_2$, $Cl_2$, $F_2$).

Multi-Valent Elements

Elements, typically transition metals, that have more than one combining capacity and can possess different charges in compounds.

Law of Conservation of Mass

A chemical law stating that during a chemical reaction, the total mass of the reactants is always equal to the total mass of the products; atoms are only rearranged, never created or destroyed.

Reactants

The starting substances located on the left side of a chemical equation that undergo a chemical reaction.

Products

The resulting ending substances located on the right side of a chemical equation produced by a chemical reaction.

Coefficient

A number placed in front of a chemical formula in a balanced equation that multiplies the entire compound to balance the number of atoms.

Subscript

A small number placed behind an atom or parenthetical group in a chemical formula that indicates how many of those atoms are present.

Exothermic Reaction

An energy-releasing chemical reaction where heat is given off to the surroundings, represented by having energy written on the product side of the equation.

Endothermic Reaction

An energy-absorbing chemical reaction that takes in heat from its surroundings, lowering the surrounding temperature, represented by having energy on the reactant side.

Synthesis Reaction

A chemical reaction in which two or more substances combine to form a single compound, following the general form $A + B \rightarrow AB$.

Decomposition Reaction

A chemical reaction in which one compound breaks down into two or more simpler substances, following the general form $AB \rightarrow A + B$.

Single Replacement Reaction

A chemical reaction in which one element replaces another element in a compound, following the general form $A + BC \rightarrow AC + B$.

Double Replacement Reaction

A chemical reaction in which elements in two different compounds exchange places, following the general form $AB + XY \rightarrow AY + XB$.

Combustion Reaction

A chemical reaction in which a carbon/hydrogen compound reacts with oxygen to form carbon dioxide and water ($C_yH_x + O_2 \rightarrow CO_2 + H_2O$).

Neutralization Reaction

A specific type of double replacement reaction in which an acid and a base combine to form a salt and water ($\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$).

Acid

A compound that turns blue litmus paper red, tastes sour, reacts with metals to produce hydrogen gas, conducts electricity in solution, and has a pH less than $7$.

Base

A compound that turns red litmus paper blue, tastes bitter, feels slippery, conducts electricity in solution, and has a pH greater than $7$.

pH Scale

A scale ranging from $0$ to $14$ measuring the potential of hydrogen ($H^+$) to determine how acidic ($0$ to under $7$), neutral ($7.0$), or basic (over $7$ to $14$) a solution is.

Indicators

Chemicals that change colour in either acids or bases to help identify the acidity or alkalinity of a substance.