Atomic Structure Flashcards

Grade 7 · Science · Flashcards

Essential vocabulary for understanding the building blocks of all matter — atoms and their parts.

Flashcards

Atom: The smallest particle of an element that still has the chemical properties of that element.
Proton: A positively charged particle in the nucleus; the number of protons defines the element (atomic number).
Neutron: A neutral (no charge) particle found in the nucleus; adds to the atom's mass but not its charge.
Electron: A negatively charged particle that moves around the nucleus in energy levels; has very little mass.
Nucleus: The small, dense core of an atom made of protons and neutrons; contains almost all of the atom's mass.
Atomic number: The number of protons in an atom's nucleus; identifies the element and determines its place on the periodic table.
Mass number: The sum of protons and neutrons in an atom's nucleus.
Isotope: Atoms of the same element with the same atomic number but a different number of neutrons (and therefore different mass numbers).
Ion: An atom that has gained or lost electrons, giving it a positive or negative electric charge.
Cation: A positively charged ion formed when an atom loses one or more electrons.
Anion: A negatively charged ion formed when an atom gains one or more electrons.
Periodic table: A systematic arrangement of all known elements ordered by atomic number, with elements of similar properties in the same column (group).
Energy level (shell): A specific region around the nucleus where electrons are likely to be found; higher shells hold electrons with more energy.