Definitions Flashcards
(43 cards)
Energy levels
Regions of space where electrons have fixed energies
Ground state
When all electrons in an atom are in there lowest energy state
Orbital
An orbital is a three dimensional region around the nucleus where there is a high probability of finding an electron with a certain amount of energy
Isotopes
Isotopes are different atoms of the same element with the same atomic number but different mass numbers
Relative atomic mass (Ar)
The relative atomic mass (Ar) is a number that compares the average mass of an atom with the mass of the C-12 atom taken to be 12 units
Cation
A positive ion and forms when an atom loses an electron
Anion
Is a negative ion and forms when an atom gains an electron
Ionization energy
The ionization energy is the minimum amount of energy required to remove an electron from an atom in the gas phase
Chemical bonding
Chemical bonding is the process by which atoms bond with each other and in this way achieve a noble gas configuration, with low potential energy
A molecule
A molecule is a group of two or more atoms which are bonded together strongly enough to behave as a single unit in a chemical reaction
Bond strength
Bond strength is the amount of energy needed to break a chemical bond
Valency
Valency is a measure of the number of chemical bonds formed by the atoms of a given element
Covalent bond
A covalent bond is a sharing of electrons between two non-metal atoms, forming a molecule
Electronegativity
Electronegativity is an indication of the attraction that an atom exerts on a shared electron pair
Non-polar covalent bond
A non-polar covalent bond (pure covalent bond) is a covalent bond where there is an equal sharing of electrons
Polar covalent bond
A polar covalent bond is a covalent bond where there is an unequal sharing of electrons leading to a dipole forming (as a result of electronegativity difference)
Intermolecular force
An intermolecular force is a weak force of attraction between molecules or between atoms of a noble gas
Van der waals forces
The attractive forces between molecules are collectively called Van der Waals forces
Dipole-dipole
Dipole-dipole forces are attractive forces between the positive end of one polar molecule and the negative end of another polar molecule
Dipole-induced dipole
A dipole-induced dipole attraction is a weak attraction that results when a polar molecule induces a dipole in an atom or in a non-polar molecule by disturbing the arrangement of electrons in the non-polar species
London forces
The London force is the weakest intermolecular force. It is a temporary attractive force that results when the electrons in two adjacent atoms or molecules occupy positions that make the atoms or molecules form temporary dipoles. London forces exist between two non-polar molecules or between atoms of noble gasses.
Hydrogen bonding
Hydrogen bonding results from the attractive force between a hydrogen atom covalently bonded to a small, very electronegative atom such as an N, O or F atom
Ionic bond
An ionic bond forms due to a transfer of electrons and subsequent electrostatic attraction
Crystal lattice
A crystal lattice is a regular 3D structure of particles
