ATOMIC THEORY DEFINITIONS Flashcards
(27 cards)
Alpha Particle
a helium nucleus with positive radition made up of 2 protons and 2 neutrons
Atomic Number
number of protons in the neucleus of an atom
Atomic orbital
the space around the neucleus of an atom where there is a high probability of finding an electron
Atomic Radius
half the distamce between the nuclei of 2 atoms of the same element joined together by a covalent bond
Aufbau Principle
Electrons will always occupy the lowest available energy level
Bond energy
the average amount of energy needed to break a band and seperate atoms of the same chemical species in the gaesous state
Cathode Rays
beams of negative particles called electrons
Compound
substance made up of 2 or more different types of atoms held together by a chemical bond
Daltons Atomic Theory
Atoms are made up of small indivisible particles and atoms of the same element are identical.
Electronegativity
the relative measure of attraction that the neuleus of an atom has for the shared electrons in a covalent bond.
Electronic configuration
the description of the number and arrangement of electrons in the energy level and sublevels of an atom.
Element
an element is a substance that cannot be broken down into simplier substances by chemical means.
Energy Level
the fixed amount of energy that an electron in an atom can have
Energy Sublevels
A group of atomic orbitals with the same energy value
First Ionisation Energy
The minimum amount of energy needed to remove the most loosely bound electron from a gaseous atom in ground state
Ground State
The minimum and most stable amount of fixed energy an electron in an atom can have, the lowest energy level.
Half Life
the time taken for half the nuclei of a radioactive sample to decay
Heinsberg’s Uncertainty Principle
states that it is impossible to know the location and speed of an electron at the same time
Hund’s Rule
The P and D sublevels fill up singularly before doubling up
INTRAmolecular forces
forces of attraction within a molecule
INTERmolecular forces
forces of attraction between different molecules
Isotopes
atoms with the same number of protons but different number of neutrons giving different mass numbers
Mass Number
number of protons and neutrons in the nucelus of the atom
MOlecule
a substance made up of two or more atoms held together by chemical bonds
