Chemical Bonding Flashcards
atoms in compounds are held together by powerful forces of attraction called
Chemical bonds
Two main types of chemical bonds
Ionic and covalent bonds
devised a beautifully simple model that unified many of the observations about chemical bonding and chemical reactions
Gilbert N. Lewis
The tendency to react in ways that achieve an outer shell of eight valence electrons is particularly common among Group 1A–7A elements and is given the special name of the
octet rule
the atom becomes a negatively charged ion called an
anion
the atom becomes a positively charged ion called a
cation
When an ion forms, the number of ______ in the nucleus of the atom remains unchanged; only the number of ______ in the valence shell of the atom changes.
protons and neutrons; electrons
Imperfections of octet rule
- Ions of period 1 and 2 elements with charges greater than 12 are unstable.
- The octet rule does not apply to Group 1B–7B elements (the transition elements), most of which form ions with two or more different positive charges.
forms when a metal loses one or more valence electrons.
Monoatomic cation
the suffix ______ is used to show the smaller charge.
-ous
the suffix ______ is used to show the larger charge.
-ic
the name of the cation is the name of the metal followed by the word
ion
A monatomic anion is named by adding
-ide
contains more than one atom.
Polyatomic ion
A chemical bond resulting from the attraction between a positive ion and a negative ion
Ionic bond
A bond resulting from the sharing of electrons between two atoms.
covalent bond
atoms bond together in such a way that each atom participating in a bond acquires a valence-shell electron configuration matching that of the noble gas nearest to it in atomic number.
Lewis model of chemical bonding
is a measure of an atom’s attraction for the electrons it shares in a chemical bond with another atom.
Electronegativity
The most widely used scale of electronegativities was devised by
Linus Pauling
The more electronegative atom gains one or more valence electrons and becomes an
Anion
the less electronegative atom loses one or more valence electrons and becomes a
Cation
The compound formed by the combination of positive and negative ions is called an
Ionic compound
this type of electron transfer to form an ionic compound is most likely to occur if the difference in electronegativity between two atoms is approximately
1.9 or greater
contains only two elements
binary compound
both of the elements are present as ions.
binary ionic compound
A bond formed by sharing a pair of electrons is called a
single bond
Electronegativity less than 0.5
nonpolar covalent bond
Electronegativity 0.5-1.9
polar covalent bond
Greater than 1.9
ionic bond
electrons are shared equally
nonpolar covalent bond
they are shared unequally
polar covalent bond
A chemical species in which there is a separation of charge; there is a positive pole in one part of the species, and a negative pole in another part
dipole
the more electronegative atom gains a greater fraction of the shared electrons and acquires a
partial negative charge
The less electronegative atom has a lesser fraction of the shared electrons and acquires a
partial positive charge
A bond formed by sharing two pairs of electrons and represented by two lines between the two bonded atoms
double bond
A bond formed by sharing three pairs of electrons and represented by three lines between the two bonded atoms
triple bond
Exceptions to the octet rule
involves molecules that contain an atom with more than eight electrons in its valence shell.
is a binary (two-element) compound in which all bonds are covalent.
binary covalent compound
The theory of resonance, developed primarily by
Linus Pauling
A theory that many molecules and ions are best described as a hybrid of two or more Lewis contributing structures
Resonance
Representations of a molecule or ion that differ only in the distribution of valence electrons
contributing structure
A molecule or ion described as a composite or hybrid of a number of contributing structures
resonance hybrid