Chemistry Basics

Chemistry

The study of hte interactions of matter with other matter and with energy.

Mass

Material that can be pulled on by gravity.

Matter

Anything that has mass, occupies space, and is composed of elements.

Element

A substance that cannot be broken down to other substances by chemical reactions.

Atom

The smallest unit of matter that still retains the properties of an element and contains protons, neutrons, and electrons.

Water

A chemical compound composed of two hydrogen atoms and one oxygen atom, essential for all known forms of life.

Proton

A subatomic particle with a positive electric charge found in the nucleus of an atom, contributing to an atom's mass and identity.

Neutron

A subatomic particle with no electric charge located in the nucleus of an atom, playing a key role in determining the stability and mass of the atom. They allow multiple positive charges (protons) to be in close proximity to one another.

Electron

A subatomic particle with a negative electric charge, found in the electron cloud surrounding the nucleus of an atom. Electrons are crucial for chemical bonding and reactions because they contain the energy of an atom.

Atomic mass unit (amu)

A standard unit of mass used to express atomic and molecular weights, with both protons and neutrons measuring about one amu each.

Energy

The capacity to cause change.

Potential energy

The energy that matter has because of its location or structure. Electrons have potential energy based upon their distance from the nucleus with further distances having more potential energy.

Chemical bond

The rearrangement of electrons between two or more atoms to create a stable connection, allowing for the formation of molecules.

Valence shell

The outermost energy/electron shell of an atom that contains electrons involved in chemical bonding.

Valence electrons

The electrons in the outermost shell of an atom that participate in chemical bonding and reactions.

Molecule

A group of atoms bonded together.

Compound

A substance formed when two or more different elements chemically bond together, resulting in a distinct molecular structure.

Ionic bond

A type of chemical bond, typically between a metal and nonmetal, which forms when the metal transfers one or more valence electrons to the nonmetal, resulting in both a positively and negatively charged ion that are then attracted to each other based on charge differences.

Covalent bond

A type of chemical bond formed when two atoms share one or more pairs of valence electrons with each other, usually between nonmetals.

Valence

Ability to form bonds, which corresponds to the number of electrons required to complete the valence shell.

Electronegativity

The tendency of an atom to attract electrons when forming a chemical bond. The more electronegative an atom, the more strongly it pulls shared electrons twoard itself.

Nonpolar covalent bond

A type of covalent bond in which electrons are shared equally between two atoms, resulting in a neutral, uncharged bond.

Polar covalent bond

A type of covalent bond where electrons are shared unequally between two atoms, leading to partial charges and a dipole moment.

Dipole

A separation of electric charge leading to a molecule having a positive end and a negative end.

Ion

A charged particle that occurs when an atom gains or loses electrons, resulting in a net positive or negative charge.

Cation

A positively charged ion formed when an atom loses one or more electrons, resulting in a net positive charge.

Anion

A negatively charged ion formed when an atom gains one or more electrons, resulting in a net negative charge.

Hydration shell

A structured layer of water molecules that surround an ion in solution, stabilizing it and facilitating interactions with other molecules.

Hydrogen bond

A type of attractive interaction between a hydrogen atom bonded to an electronegative atom (such as oxygen or nitrogen) and another electronegative atom. It plays a crucial role in the properties of water and biological molecules.

Cohesion

The tendency of molecules of the same substance to stick together, which is particularly evident in water due to hydrogen bonding.

Single bond

A type of chemical bond where two atoms share one pair of electrons, resulting in a strong attraction between the bonded atoms. Single bonds are common in organic molecules and are represented by a single line in chemical structures.

Double bond

A chemical bond between two atoms involving the sharing of two pairs of electrons. It is stronger than a single bond and provides greater stability to the molecule.

Periodic Table

A systematic arrangement of chemical elements, organized by increasing atomic number, which provides information about each element's properties and relationships.

Atomic number

The number of protons found in the nucleus of an atom, which determines the identity of an element and its position in the periodic table.

Chemical symbol

A one- or two-letter abbreviation used to represent a chemical element. It is derived from the element's name in English or Latin and is used universally in chemical formulas and equations.

Atomic mass/mass number

The weighted average mass of an atom (or one mole) of an element, measured in atomic mass units (amu), which is roughly the combined number of protons and neutrons in an atom. Mass number and atomic number can be used to calculate the number of neutrons in an atom by subtracting the atomic number from the mass number.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different atomic masses. Isotopes may be stable or radioactive.

Radioactive isotope

An isotope that is unstable and decays over time, emitting radiation in the process. These isotopes can have various applications, including in medical imaging and treatment.

Periods

The horizontal rows in the periodic table that signify elements with increasing atomic numbers and similar energy levels.

Groups

The vertical columns in the periodic table that group elements with similar chemical properties and the same number of valence electrons.

Carbon

A non-metal element with the atomic number 6, essential for life and known for its ability to form various compounds based upon its valence, including organic, biological molecules such as carbohydrates, lipids, proteins, and nucleic acids.