Science 20F Chemistry in Action

Vocabulary practice flashcards covering atomic structure, periodic table trends, ionic and covalent bonding, balancing chemical equations, types of chemical reactions, and acids and bases from Science 20F Chemistry in Action.

Atom

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

Electron ($e^-$)

A very tiny, light subatomic particle that carries a negative electrical charge ($-$) and orbits the nucleus.

Proton ($p^+$)

A large and heavy subatomic particle located in the nucleus that carries a positive electrical charge ($+$).

Neutron ($n^0$)

A large and heavy subatomic particle located in the nucleus that carries no electrical charge ($0$).

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 found in an element's nucleus, which also equals the number of electrons in a neutral atom.

Nucleus

The central core of an atom where protons and neutrons are located and where all the mass of the atom is found.

Ion

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

Cation

A positively charged ion formed when an atom (typically a metal) loses electrons, resulting in more protons than electrons.

Anion

A negatively charged ion formed when an atom (typically a non-metal) gains electrons, resulting in more electrons than protons.

Bohr Model

A diagram used to represent an atom by showing protons and neutrons inside a circular nucleus and electrons orbiting in specific energy shells.

Valence Shell

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

Valence Electrons

Electrons located in the outermost electron shell that determine an element's chemical properties and participate in chemical bonding.

Lewis Dot Diagram

A shorthand diagram in which valence electrons are represented as dots placed symmetrically around the element's chemical symbol.

Metals

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

Ductile

The physical property of a metal describing its ability to be stretched into thin wires.

Malleable

The physical property of a metal describing its ability to be hammered or pressed out of shape without breaking or cracking.

Non-Metals

Elements found to the right of the zigzag line on the periodic table that are mostly gases or brittle solids at room temperature and poor conductors of electricity.

Metalloids

Elements found along the zigzag line on the periodic table (excluding aluminum) that exhibit properties of both metals and non-metals.

Period

A horizontal row on the periodic table, numbered 1 to 7 from top to bottom, which indicates the number of electron shells an element possesses.

Family (Group)

A vertical column on the periodic table containing elements that share common chemical properties and identical numbers of valence electrons in tall columns.

Alkali Metals

Family 1A metals that contain only 1 electron in their valence shell and are very reactive, especially with air and water.

Alkaline Earth Metals

Family 2A metals containing 2 valence electrons that are reactive, though less reactive than alkali metals.

Chalcogens

Family 6A non-metals that contain 6 electrons in their outermost valence shell.

Halogens

Family 7A elements that have 7 valence electrons and represent the most reactive group of non-metals.

Noble Gases

Family 8A non-metals that are all gases at room temperature and do not react with other elements because they have full valence shells.

Ionic Bond

A chemical bond formed between a metal and a non-metal where the metal gives away electrons to form a cation and the non-metal accepts electrons to form an anion.

Multi-Valent Elements

Elements (often transition metals) that possess more than one combining capacity and can exhibit different positive ionic charges indicated by Roman numerals.

Covalent Bond

A chemical bond formed when two non-metal atoms share electrons to produce molecular compounds.

Diatomic Molecules

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

Subscript

A small number written to the lower right of a chemical symbol indicating the number of atoms of that specific element in a molecule or formula unit.

Coefficient

A whole number placed in front of a chemical formula in an equation that multiplies all atoms in that compound to balance the equation.

Law of Conservation of Mass

Lavoisier's principle stating that the total mass of the reactants in a chemical reaction always equals the total mass of the products because atoms are neither created nor destroyed, only rearranged.

Word Equation

A representation of a chemical reaction where the names of the reactants and products are written out in words.

Skeleton Equation

An equation that summarizes a chemical reaction using chemical formulas without balancing coefficients.

Balanced Equation

A chemical equation in which coefficients are adjusted so that the total number of each type of atom is equal on both sides of the reaction arrow.

Exothermic Reaction

A chemical reaction that releases energy, usually in the form of heat, having energy written as a product on the right side of the equation.

Endothermic Reaction

A chemical reaction that absorbs energy from its surroundings, lowering the surrounding temperature and showing energy as a reactant on the left side of the equation.

Synthesis Reaction

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

Decomposition Reaction

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

Single Replacement Reaction

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

Double Replacement Reaction

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

Combustion Reaction

A chemical reaction in which a hydrocarbon combines with oxygen to produce carbon dioxide, water, and heat energy, following the general formula $C_yH_x + O_2 \rightarrow CO_2 + H_2O$.

Neutralization Reaction

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

Acid

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

Base

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

pH Scale

A measurement scale ranging from 0 to 14 used to determine the potential of hydrogen ($H^+$) and quantify how acidic (less than 7), neutral (7.0), or basic (greater than 7) a solution is.

Indicator

A chemical substance that changes color in the presence of an acid or a base to identify whether a solution is acidic or basic.