Chemistry Final Exam Study Sheet

Proton

A stable, positively charged subatomic particle found in the nucleus of every atom

Neutron

A subatomic particle found in the nucleus of an atom, which has no charge.

Electron

A stable, negatively charged subatomic particle that orbits the nucleus of an atom.

Isotope

Atoms of the same element with different numbers of neutrons, resulting in different mass numbers.

Chemical Change

A process where substances are transformed into different substances with new chemical properties. It often involves a reaction that alters the composition and structure of molecules.

Molecule

A group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.

Who developed the Atomic Theory of Matter

John Dalton, an English chemist, proposed that matter is composed of atoms, which are indivisible particles that combine in whole-number ratios to form compounds.

Hydrogen

H

Helium

He

Lithium

Li

Beryllium

Be

Boron

B

Carbon

C

Nitrogen

N

Oxygen

O

Flourine

F

Neon

Ne

Sodium

Na

Magnesium

Mg

Aluminum

Al

Sillicon

Si

Phosphorus

P

Sulfur

S

Chlorine

Cl

Argon

Ar

Potassium

K

Calcium

Ca

Weight

The forced exerted on an object due to gravity, representing how strongly gravity pulls on an objects mass

Mass

A fundamental, intrinsic property of matter that measures the amount of "stuff" or material within an object

How does kinetic energy relate to temperature

As temperature increases, the average kinetic energy and molecular motion of particles increase

Ion

An atom or molecule with a net electric charge due to the loss or gain of one or more electrons

Cation

A positively charged ion, formed when an atom or molecule loses one or more valence electrons

Anion

A negatively charged ion formed when an atom or molecule gains one or more electrons, giving it more electrons than protons

Atomic number

The number of protons found in the nucleus of an atom

Mass number

The total count of protons and neutrons (nucleons) in an atomic nucleus

States of matter and their characteristics

Solids- defined volume and shape, high density

Liquids- Definite volume but indefinite shape

Gas- Indefinite shape and volume

Chemical formulas

A concise, symbolic representation of a molecule or compound, using element symbols from the periodic table, numbers (subscripts), and symbols like parentheses to indicate the types and proportions of atoms present

Naming and writing formulas for ionic and covalent compounds

Ionic compounds (metal + nonmetal) are named by stating the cation followed by the anion (ending in -ide), using Roman numerals for variable-charge metals. Covalent compounds (nonmetal + nonmetal) use Greek prefixes (di-, tri-, tetra-) to indicate the number of atoms, with the second element ending in -ide

Calculating molecular mass

locate the atomic mass of each element on the periodic table, multiply by the number of atoms in the formula (subscripts), and sum these values

Avogadro’s number

The fundamental physical constant representing the number of constituent particles (atoms, molecules, or ions) in one mole of a substance

Mole

6.022 × 10²³ particles (atoms, molecules).

Chemical equations

A symbolic representation of a chemical reaction, using formulas and symbols to show reactants (left) transforming into products (right)

Reactants

A substance that enters into and is altered during a chemical reaction

Products

The new substances formed as a result of a chemical reaction

→

Signifies a chemical reaction or transformation, pointing from reactants (starting materials) to products

Law of Conservation of Mass

Mass in a closed system is neither created nor destroyed by chemical reactions or physical changes

Balancing chemical equations

Ensures the number of atoms for each element is equal on both sides, adhering to the law of conservation of mass

Combination reaction

A + B → AB

Decomposition reaction

AB → A + B

Single displacement

AB + C → AC + B

Double displacement

AB + CD → AC + BD

The assumption of kinetic theory of matter

These particles are in motion, negligible volume, exert no intermolecular forces and experience elastic collisions.

Atm, mmHg, and Pa are units used to measure

Pressure

Boyle’s Law and formula

The pressure (P𝑃) of a given mass of an ideal gas is inversely proportional to its volume (

V 𝑉), provided the temperature remains constant. If volume increases, pressure decreases, and vice versa. The formula is

𝑃1𝑉1=𝑃2𝑉2

Diffusion

The net, passive movement of particles (atoms, ions, or molecules) from a region of higher concentration to a region of lower concentration, driven by thermal energy and random molecular motion

Heat

the transfer of thermal energy between systems or objects due to a temperature difference, typically flowing from a hotter body to a colder one

Endothermic reactions

A chemical or physical process that absorbs energy, usually in the form of heat, from its surroundings

Exothermic reactions

A chemical process that releases energy into its surroundings, usually in the form of heat or light, resulting in a net increase in temperature

Quantum numbers

a set of four numerical values (𝑛,ℓ,𝑚ℓ,𝑚𝑠) that act as an "address" for electrons in an atom, describing their energy, orbital shape, orientation, and spin.

Electron shell or energy level

discrete energy levels or shells around an atom's nucleus, starting with the lowest energy level (innermost shell) first

Subshells and the number of electrons each can hold

Subshells (𝑠,𝑝,𝑑,𝑓) are energy sublevels within electron shells that define the shape of orbitals. They hold a maximum of 2, 6, 10, and 14 electrons, respectively, based on having 1, 3, 5, or 7 orbitals

Valence electrons

The electrons located in the outermost electron shell of an atom

Lewis symbols

Represents an element's symbol surrounded by dots representing its valence electrons

Periodic Law

When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic repetition

Groups

18 vertical columns, ranging from 1 to 18

Row

Seven horizontal rows

Group one elements

Alkali metals

Group two elements

Alkaline earth metals

Group seven-teen elements

Halogens

Group eight-teen elements

Noble gases

Bonding

The enduring attraction between atoms, ions, or molecules that enables the formation of stable chemical compounds

Octet rule

Fundamental chemical principle stating that atoms tend to gain, lose, or share electrons to achieve a stable configuration of eight valence electrons

Acid

a chemical substance that produces hydrogen ions (H+𝐻+) in aqueous solution, tastes sour, turns blue litmus paper red, and has a pH less than 7

Base

A substance that can neutralize acids, feel slippery, taste bitter, and have a pH greater than 7

PH scale

Measures how acidic or basic (alkaline) a water-based solution is, typically ranging from 0 to 14

Neutralization

A chemical reaction where an acid and a base react to form water and a salt

Saturated solution

A chemical solution containing the maximum concentration of a dissolved solute for a given amount of solvent at a specific temperature and pressure

Supersaturated solution

An unstable, non-equilibrium state containing more dissolved solute than a saturated solution can normally hold at a given temperature

Molarity

The molar concentration of a solution

Boiling point elevation

The increase in a solvent's boiling point caused by adding a non-volatile solute, making the solution boil higher than the pure solvent

Freezing point elevation

A colligative property where adding a non-volatile solute (like salt) to a solvent (like water) lowers its freezing temperature

Electrolytes

A substance that produces electrically conducting solutions when dissolved in a polar solvent

Catalyst

A substance that speeds up a chemical reaction, or enables it to occur at lower temperatures/pressures, without being consumed in the process

Enzymes

Highly specific biological catalysts, typically proteins, that speed up chemical reactions in living organisms by lowering the activation energy required to initiate them

Reversible reactions

A process where reactants form products, and those products can simultaneously turn back into reactants

Half life

The time required for half of a radioactive sample to decay or for half of a reactant to be consumed in a reaction

Alpha rays

Positively charged radiation composed of two protons and two neutrons

Beta rays

high-speed, high-energy electrons or positrons emitted by unstable atomic nuclei during radioactive decay

Gamma rays

The highest-energy, shortest-wavelength form of electromagnetic radiation

Nuclear fission

The process where the nucleus of a heavy, unstable atom (such as uranium-235) is split into two or more smaller, lighter nuclei

Nuclear fusion

The process of combining light atomic nuclei (like hydrogen isotopes) into a heavier one, releasing immense energy

Acidic

Has a sour or sharp taste and contains an acid

Basic

A substance that acts as a base, usually having a pH greater than 7

Neutrual

A substance with no overall electrical charge

Coeffcient

a whole number placed in front of a chemical formula in an equation

How to write formulas

Identifying element symbols, determining their ratios (using charges for ionic or prefixes for covalent), and using subscripts to indicate the number of atoms

How to balance chemical equation

Adjust the numbers in front of the formulas (coefficients) so you have the exact same number of each type of atom on both the reactant and product sides