Chemistry Lecture Notes Flashcards

A collection of flashcards based on key concepts and definitions in chemistry from the lecture notes.

What is the definition of an atom?

The smallest part of an element that can exist on its own.

Who discovered the electron?

Thomson discovered the electron and proposed the 'plum pudding model'.

What does the atomic number represent?

The number of protons in an atom.

What defines isotopes?

Atoms that have the same number of protons but a different number of neutrons.

What is an ionic bond?

The attraction between oppositely charged ions.

What is the definition of a covalent bond?

A shared pair of electrons between two atoms.

What characterizes a metallic bond?

The attraction between delocalised electrons and a regular lattice of positive ions.

What is the difference between a cation and an anion?

A cation is a positive ion formed when an atom loses electrons; an anion is a negative ion formed when an atom gains electrons.

What is the empirical formula?

The simplest whole number ratio of atoms in a molecule.

How is relative atomic mass defined?

The mass of an atom compared to the mass of carbon-12.

What is the significance of the group number in the periodic table?

It indicates the number of electrons in the outer shell of the elements.

What is a saturated solution?

A solution in which no more solute will dissolve at a given temperature.

What does the term 'limiting reactant' refer to?

The reactant that is completely used up in a chemical reaction and limits the amount of product formed.

What occurs during neutralization reactions?

An acid reacts with a base to produce a salt and water.

What is the purpose of using indicators in acid-base reactions?

To change color in the presence of an acid or an alkali.

What do the halogens gain during reactions?

An electron, forming negative ions with a 1- charge.

What defines transition metals in the periodic table?

They can form compounds with different charges and usually have colored compounds.

What is the practical method for determining solubility?

Add a solid to water, heat until dissolved, cool and observe the temperature at which crystals appear.

What happens to solubility of gases as temperature increases?

The solubility of gases decreases with increasing temperature.

How is a salt formed?

A salt is formed when some or all hydrogen ions in an acid are replaced by metal ions or ammonium ions.

What is the definition of an ion?

An ion is an atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

What is a molecular compound?

A compound consisting of molecules formed from atoms of two or more different elements.

What is the definition of a compound?

A substance formed when two or more elements chemically bond together.

What are polar molecules?

Molecules that have a partial positive charge on one side and a partial negative charge on the other, due to unequal sharing of electrons.

What role do valence electrons play in bonding?

Valence electrons are the electrons in the outermost shell of an atom and are involved in forming bonds with other atoms.

What is a chemical reaction?

A process in which one or more substances are converted to one or more different substances.

How do metals typically behave in reactions?

Metals tend to lose electrons in chemical reactions and form cations.

What is the octet rule?

The principle that atoms tend to bond in such a way that they have eight electrons in their valence shell, achieving a stable electronic configuration.

What happens in a redox reaction?

A reduction-oxidation (redox) reaction involves the transfer of electrons between two species, with one being oxidized and the other being reduced.

What is the significance of a catalyst in a chemical reaction?

A catalyst is a substance that speeds up the rate of a chemical reaction without being consumed in the process.

What defines elements in a chemical reaction?

Elements are pure substances that cannot be broken down into simpler substances by chemical means.

What is an endothermic reaction?

A reaction that absorbs heat from the surroundings.

What is an exothermic reaction?

A reaction that releases heat to the surroundings.

What is a solvent?

A substance that dissolves a solute, resulting in a solution.

What is a solute?

A substance that is dissolved in a solvent.

What are the products of combustion reactions?

The products of combustion reactions are typically carbon dioxide and water.

What is the definition of pH?

pH is a scale used to specify the acidity or basicity of an aqueous solution.

What defines a strong acid?

A strong acid is an acid that completely dissociates in solution.

What defines a weak acid?

A weak acid is an acid that partially dissociates in solution.

What is a base?

A base is a substance that can accept hydrogen ions or donate electron pairs in reactions.

What is a buffer solution?

A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added.

What is crystallization?

Crystallization is the process where a solid forms from a liquid or gas, typically when