Chapter 4 - The Periodic Table Flashcards
Define: Atoms
The particles that make up all materials; the smallest part of an element that can take part in a chemical reaction
Define: Atomic Number
The number of protons in an atom
Define: Electron Configuration
The arrangement of electrons in electron shells
Define:Electron Shells
Also known as energy levels, the regions surrounding the nucleus where electrons may be found.
Define: Element
A substance composed of atoms with the same atomic number; 118 are known to exist.
Define: Energy Levels
Also known as electron shells, the regions surrounding the nucleus where electrons may be found.
Define: Ground State
The lowest energy arrangement of an atom’s electrons in energy levels(shells)
Define: Indirect Evudence
Evidence that does not involve direct observation
Define: Nucleus
The heavy core at the centre of an atom, made of protons and neutrons
Define: Actinides
A special block of metallic elements with atomic numbers 90-103
Define: Groups
Vertical columns of the periodic table; group number is equal to the number of electrons in the outer shell of atoms of the elements in that group
Define: Lanthanides
A special block of metallic elements with atomic numbers 58-71
Define: Periodic Table
A list of all the known elements, arranged horizontally in order of increasing atomic number and vertically according to the number of electrons in the outer shell.
Define: Periods
Horizontal rows of e periodic table; period number of and element is equal to the number of electron shells
Define: Transition Elements
A special block of metallic elements covering elements from groups 3-12
