Atomic Structure Key Vocabulary

Study Notes

Atom: The smallest unit of matter that retains the properties of an element
Element: A substance consisting of atoms with the same number of protons in the nucleus
Proton: A positively charged subatomic particle found in the nucleus of an atom
Neutron: A neutral subatomic particle found in the nucleus of an atom
Electron: A negatively charged subatomic particle found in orbitals around the nucleus of an atom
Nucleus: The central part of an atom containing protons and neutrons

Chemical bond: A force that holds two or more atoms together
Molecule: A group of atoms bonded together
Ion: An atom or group of atoms with an electric charge
Valence electron: An electron in the outermost energy level of an atom, involved in bonding
Covalent bond: A bond formed by sharing one or more pairs of valence electrons
Ionic bond: A bond formed by the transfer of electrons, resulting in ions with opposite charges

Chemical reaction: A process in which one or more substances are converted into new substances
Reactant: A substance that is consumed during a chemical reaction
Product: A substance formed during a chemical reaction
Catalyst: A substance that speeds up a chemical reaction without being consumed
Activation energy: The minimum energy required for a chemical reaction to occur

Physical property: A characteristic of a substance that can be observed without changing its chemical composition
Chemical property: A characteristic of a substance that can be observed only through a chemical change
Acid: A substance that donates a proton (H+ ion)
Base: A substance that accepts a proton (H+ ion)
pH: A measure of the concentration of hydrogen ions in a solution

An atom is the smallest unit of matter that retains the properties of an element, which has atoms with the same number of protons in the nucleus.
A proton is a positively charged subatomic particle found in the nucleus of an atom.
A neutron is a neutral subatomic particle found in the nucleus of an atom.
An electron is a negatively charged subatomic particle found in orbitals around the nucleus of an atom.
The nucleus is the central part of an atom containing protons and neutrons.

A chemical bond is a force that holds two or more atoms together, forming a molecule.
An ion is an atom or group of atoms with an electric charge.
Valence electrons are electrons in the outermost energy level of an atom, involved in bonding.
A covalent bond is a bond formed by sharing one or more pairs of valence electrons.
An ionic bond is a bond formed by the transfer of electrons, resulting in ions with opposite charges.

A chemical reaction is a process in which one or more substances are converted into new substances, involving reactants and forming products.
A catalyst is a substance that speeds up a chemical reaction without being consumed.
Activation energy is the minimum energy required for a chemical reaction to occur.

A physical property is a characteristic of a substance that can be observed without changing its chemical composition.
A chemical property is a characteristic of a substance that can be observed only through a chemical change.
An acid is a substance that donates a proton (H+ ion).
A base is a substance that accepts a proton (H+ ion).
pH is a measure of the concentration of hydrogen ions in a solution.