chap 5: chemical bonding I Flashcards
what are electron donors and electron acceptors.
electron acceptors: Larger negative value for electron affinity of an atom indicates that the atom prefers to hold on to an extra electron
electron donors: Atoms with low ionization energy lose an electron relatively easily
Note; e.a like F, Cl, and Br have high IE and high EA, while e.d like alkali metals have low IE and smaller EA
electronegativity vs electron affinity
electronegativity is the ability of an atom to attract an electron to itself which is different from gaining an electron.
electronegativity trend
increases accross the period and decreases down the group.
polar bonds vs non-polar bonds.
polar bonds have a dipole moment, while non-polar bonds have no dipole moment.
polar molecules vs non-polar molecules.
polar molecules is when bond dipole moments vectors point in the same direction, while in non-polar the bond dipole moments point in opp direction and cancel each other out.
Polar molecules with polar bonds and non-polar molecules with non-polar bonds.
Water is a polar molecule with polar bonds, and carbon dioxide is a non-polar molecule with polar bonds btn O and C, but they cancel each other out to form non-polar molecule (also Hydroben Trifluoride)
Percent ionic character trend with respect to electronegativity.
It increases with an increase in electronegativity.
bond energies and their properties
the energy needed to break a bond of 1 mol of gaseous molecules
- bonds get stronger across the row
- weaker down the column
- the energy of a given bond can change slightly from one molecule to another (ex, CH4, C2H6,….)
endothermic and exothermic with respect to bonds
- when bonds are formed (exothermic)
- when bonds are broken (endothermic)
non-polar molecules that violet the electronegativity difference theory
- CH, Br-Cl, and C-S
