chemical bonding Flashcards
chapter 4
what is a chemical bond?
a strong attractive force that exists between certain atoms in a substance
what are the 3 types of chemical bonds? Give a brief description of each.
- ionic bonds- between a metal and a nonmetal
- covalent bonds- between 2 nonmetals
- metallic bonds- between metals
what is a covalent bond?
chemical bond formed by sharing a pair of electrons
what is bond length?
the distance between atoms when energy is at a minimum
what is an orbital overlap?
as the hydrogen atoms move closer together, the electron of each atom is attracted to both its own nucleus and the nucleus of the second atom
what is ionic bonding?
chemical bond formed by the electrostatic attraction between positive and negative ions
what are the properties of ionic compounds?
-hard, rigid, and brittle
-solids are not conductive, dissolved compounds are conductive
-high melting points
how do you name cations?
-named for the parent atom followed by “ion”
- if the metal can form more than one cation, they are named for the parent, followed by charge in roman numerals in parenthesis followed by the word “ion”
how do you name anions?
-monoatomic anions are named by dropping the end of the element name and adding the suffix “-ide” followed by the word “ion”
how do you name inorganic compounds (cation and anion)?
-the cation is always named first with the name of the cation without the word “ion”
-the anion is named second with the name of the anion without the word “ion” and “-ide” added to the end
how do you name oxyanions?
the oxyanions that end in “-ite” each have one less oxygen than the oxyanions that end in “-ate”
what is a binary molecular compound?
compounds that contain two nonmetals
what are the naming rules for binary molecular compounds?
-name the first element using the element name
-name the second element using the element root + the “-ide” suffix
-add a prefix to each name to indicate the number of atoms of that element
name P4S3
tetraphosphorus trisulfide
name CO
carbon monoxide
name XeF6
xenon hexafluoride
what is a binary acid?
aqueous solution of a compound containing hydrogen and a nonmetal
how do you name binary acids?
using the prefix “hydro-“ before the element stem and adding the suffix “-ic acid”
name HF (aq)
hydrofluoric acid
what is an oxoacid?
contain hydrogen, oxygen, and a third central atom
how do you name oxoacids?
-change the “-ate” suffix to “-ic”
change an “-ite” suffix to “-ous”
-add the word “acid”
name HNO3
nitric acid
name H2SO4
sulfurous acid
what is a lewis electron-dot formula? how are electron pairs represented?
-formula using dots to represent valence electrons
-two dots
what is a bonding pair? how are they represented on lewis electron-dot formulas?
-electron pair that is between two atoms
-one line for each bonding pair
what are lone pair electrons?
electron pairs that are not bonding
what is a single bond?
one pair of electrons is shared by two atoms
what is a double bond?
two pairs of electrons are shared b ytwo atoms
what is a triple bond?
three pairs of electrons are shared by two atoms
what is the octet rule? are there any exceptions?
-in forming covalent bonds, atoms tend toward having a full eight electrons in their valence shell
-hydrogen is an exception: it has two electrons in its valence shell
what are the steps for writing a Lewis electron dot formula?
- calculate the number of valence electrons
- write the skeleton structure of the molecule or ion
- distribute electrons to the atoms surrounding the central atom or atoms to satisfy the octet rule
4.distribute the remaining electrons as pairs to the central atom(s)
what is delocalized bonding?
a bonding pair of electrons is spread over a number of atoms rather than being localized between two atoms
put this in order from increasing to decreasing bond length:
C-C
C=C
C≡C
- C-C
- C=C
- C≡C
put this in order from increasing to decreasing bond strength:
C-C
C=C
C≡C
- C≡C
- C=C
- C-C
what is electronegativity?
measure of the ability of an atom in a molecule to draw bonding electrons to itself
