Ionic bonding Flashcards
what is a chemical bond
the attractive force that holds two or more atoms together in a molecule
involves valence electrons
what is coulomb’s law
F = kq1q2/r^2
the strength of the electrostatic interaction is proportional to the size of the charge and inversely proportional to the distance
what is electronegativity
the ability of an atom to attract towards itself the electrons in a chemical bond
what does electronegativity depend on
- the number of protons in the nucleus
- the distance from the nucleus/size of the atom
- the amount of screening by inner electrons (i.e. the number of full shells between the valence shell and the nucleus)
what is the most electronegative element
fluorine because it is small and has a high nuclear charge
which are the 4 strongest bonds
ionic bonds
covalent bonds
dative covalent bonds
metallic bonding
which are the 3 weakest bonds
hydrogen bonds
dipole-dipole bonds
Van der Waal’s bonds
how are ionic bonds formed
formed when one or more electrons are fully transferred between atoms between metals and nonmetals
properties of ionic bonds
- non-directional
- broken when compounds dissolve in polar solvents such as water (ionic compounds dissolve easily in water and other polar solvents)
- structure breaks down when the compound is melted (conducts electricity when molten)
- ionic compounds are not charged overall
the ionic lattice
- every ion is attracted to all other ions with opposite charges resulting in a repeating 3D pattern of anions and cations in the solid state
what structure is an ionic lattice
giant
define lattice energy
the enthalpy of formation of forming one mole of the ionic solid from its gaseous ions
factors favouring ionic bonding
easy cation formation - low ionization energy of the metal easy anion formation - high electron affinity/electronegativity of the nonmetal - small size of nonmetal low charge on the anion large electronegativity difference between the combining atoms high lattice energy of ionic compounds
define polarisation
distortion of the electron cloud of the atom
- the smaller the ion and the higher the charge, the more polarizing power it has
which has a higher polarising power anions or cations
cations
