Unit 9.1 Study Guide | Atoms, Elements & the Periodic Table

Flashcards based on the key concepts of atoms, elements, compounds, and the periodic table from the study guide.

Proton

A subatomic particle with a positive charge found in the nucleus of an atom.

Neutron

A subatomic particle with no charge that is located in the nucleus.

Electron

A subatomic particle with a negative charge found in the electron cloud outside the nucleus.

Nucleus

The center of an atom, containing protons and neutrons, and holding most of the atom's mass.

Electron cloud

The region surrounding the nucleus where electrons are located, making up most of the atom's volume.

Element

A pure substance made of only one type of atom.

Compound

A substance composed of two or more different elements that are chemically bonded together.

Molecule

A group of two or more atoms bonded together, which can be the same or different elements.

Atomic number

The number of protons in an atom, which is unique to each element.

Group

A column in the periodic table where elements have similar properties.

Period

A row in the periodic table where the atomic number increases from left to right.

Scientific theory

A well-tested explanation that is supported by extensive evidence from experiments.

Levels of Organization

The hierarchy of biological structures, from least specialized (Cell) to most specialized (Organism).