Atoms Flashcards
Atoms
the smallest part of an element that can still be recognised as that element
Atomic number
the number of protons (which equals the number of electrons) in an atom. It is sometimes called the proton number
Compound
a substance made when two or more different elements are chemically bonded together
diatomic element
two atoms with the same atomic number that are chemically bonded, for example, the oxygen molecule, 02
electron
a tiny particle with a negative charge. Electrons orbit the nucleus of atoms or ions in shells
electronic structure
a set of numbers to show the arrangement of electrons in their shells (or energy levels)
element
a substance made up of only one type of atom. An element cannot be broken down chemically into any simpler substance
groups
the vertical columns (labelled 1 to 7 and 0) in the periodic table are called groups. The number of electrons in the outer shell of the atoms of an element tell you the group to which the element belongs
mass number
the number of protons plus neutrons in the nucleus of an atom
mixture
two or more different substances that are not chemically joined and retain their distinct identities.
molecule
neutral particles made of two or more non-metal atoms covalently bonded together.
neutron
a dense particle found in the nucleus of an atom. It is electrically neutral, carrying no charge
noble gases
the very unreactive gases found in Group 0 of the periodic table. Their atoms have very stable electronic structures
nucleus (of an atom)
the very small and dense central part of an atom that contains protons and neutrons
period
the horizontal rows in the periodic table are called periods. The period corresponds to the number of occupied shells in atoms of the element.
