Chemical Bonding Flashcards
A compound is…
a substance that is made up of 2 or more elements chemically combined
Octet rule
When bonding occurs, electrons tend to reach an electron arrangement with eight electrons in outer shell
Ionic bond
is the force of attraction between oppositely charged ions in a compound
A transition metal
Is one that forms at least one ion with a partially filled d-sublevel
A covalent bond
is one that involves the sharing of electrons
The valency of an element
The number of atoms of hydrogen or an other monovalent element with which each atom of the element combines
VSEPR theory
STATES: the shape of a molecule depends on the number of pairs of electrons in the valence shell of the central atom. Since electrons are negatively charged, the electron pairs repel each other and arrange themselves in space so as to be as far away as possible.
Electronegativity
the relative attraction an atom in a molecule has for the shared pair of electrons in a covalent bond
electronegativity difference greater than 1.7
ionic E.g NaCl= Na(3.16)-Cl(0.93) = 2.23
electronegativity difference less than 1.7
covalent E.g H2O= O(3.44)-H(2.2)= 1.24
Polar bond
is a covalent bond in which the electrons are shared unevenly (electronegativity difference between 1.7 and 0.4 not inclusive)
A dipole
is a pair of electronic charges of equal magnitude but opposite sign, separated by some (usually small) distance
ionic bonds usually happen between
metal+ non metal
covalent bonds usually happen between
2 non-metals
3 types of intermolecular bonding
Van der Waals forces (weakest)
Dipole-Dipole forces
Hydrogen bonds (Strongest)
Van der Waals forces are…
weak attractive forces between molecules resulting from the formation of temporary dipoles
Dipole-Dipole forces are…
forces of attraction between the negative pole of one and the positive pole of another
Hydrogen binds are…
particular types of dipole dipole attractions between molecules in which hydrogen atoms are bonded to nitrogen, oxygen or fluorine. The hydrogen atom carried a partial positive charge and is attracted to the electronegative atom in another molecule. Thus, the hydrogen bond acts as a bridge between two electronegative atoms in seperate molecules
