Atomic Structure Flashcards
Atom
The smallest unit of matter; the simplest particle that an element can be split into while still being that element.
Atomic Number
The number of protons in an atom of that element.
Mass Number
The number of protons plus the number of neutrons in an atom.
Isotopes
Atoms that have the same atomic number (are the same element) but a different mass number (have a different number of neutrons)
Shell Diagram
Shows the electron shells drawn around the nucleus, with the correct number of electrons shown in each shell
Ion
An atom (or group of atoms) that has gained or lost electrons and is now charged.
Group
A column of elements in the Periodic Table, which have the same number of electrons in their outer shell
Period
A row of elements in the Periodic Table, which have the same number of electron shells
Valence Electrons
The electrons in the outermost shell of an atom or ion.
Alkali Metal
An element in Group 1 of the Periodic Table
Halogen
An element in Group 7 of the Periodic Table
Noble Gas
An element in Group 8 (sometimes called Group 0) of the Periodic Table
Element
A substance made from only one type of atom (ie all the atoms have the same atomic number)
Compound
A substance made from more than one type of atom, chemically bonded together
Mixture
A composition of two or more substances that are not chemically combined with each other and can be separated using physical techniques (ie a chemical reaction is not required)
