Chapter 8 Flashcards
What is the octet rule?
atoms tend to gain, lose or share electrons untill they are surrounded by 8 valence electrons
What does ionic compounds consist of?
a metal and a nonmetal
In ionic compounds are they sharing or transfering electrons?
transfer
Why are ionic compounds generally stable?
the electrostatic attraction between ions of opposite charge
Why does ionic compounds from a crystalline solid?
the attraction draws the ions together, releasing energy
What is lattice energy?
the energy required to completely seperate one molf of a solid ionic comound into its gaseous ions
What does the lattice energy reaction look like?
Ex:NaCl(s)
S –> +(g) + -(g) ∆Hlattice energy= +__kJ/mol
Ex: NaCl(s) —> Na+(g) + Cl-(g) ∆HLattice=+ 788 kJ/mol
What does lattice energy depend on?
the charge and the distance
As charge increases what happens to the lattice energy?
lattice energy increases
As you go across the period what does lattice energy do?
increases
As distance increases what happens to the lattice energy?
decreases
As we go down a group what does lattice energy do?
decreases
Can group 1A atoms be a 2+ ion?
No
What groups can only be an ion that has its same normal charge?
1A,2A,3A,5A,6A,7A
What are covalent bonds usually made up of?
nonmetals and nonmetals
What is bond polarity?
a measure of the degree to which the electrons are shared unequally between two atoms in a chemical bond
What is a nonpolar covalent bond?
a covalent bond in which the electrons are shared equally
What is a polar covalent bond?
a covalent bond in which the electrons are not shared equally
What is electronegativity?
the ability of an atom in a molecule to attract electrons to itself
What does electronegativty do as you go across the period?
increases
What does electronegativty do as you go down a column?
decreases
What is the most electronegative atom?
F
What does the electrongeativty difference need to be in order to nonpolar covlanet?
0-0.4
What does the electronegativty need to be in order for it to be polar covalent?
0.5-1.9
What does the elctronegativty need to be in order to be ionic?
2.0-and greater
Which element gets the partial negative charge?
the most electronegative
Which way does the dipole moment point to?
the one with the partial negative or the one that is more electronegative
What is the equation to find dipole moment?
dipole moment=Qr(Q is charge and r is distance)
How to find formal charge?
of valence electrons - bonds(1/2)
which element in a compound should get the formal charge?
the most electronegative
What is the dominat lewis strucure?
the one that has the most zero formal charges and if there is a formal charge its on the most electronegative
What is a reounce strusture?
the same compound drawed a different way
As number of bond increases what happens to the bond length?
decreases
When you have renouance strucutres how do you find the longest bond lenght?
find the average so if there is two single bonds and one double bond you do 4/3?
What is the first exception to the octet rule?
molecules and polyatomic ions containg odd number of electrons
What is the second exception to the octet rule?
molecules and polyatomic ions in which an atom has fewer than an octet of valenece electrons
What is the third exception to the octet rule?
molecules and polyatomic ions in which an atom has more than an octet of valence electrons
What period can have more than electrons than eight?
from period 3 and below
What type of bond is stronger?
triple bond is the strongest bond
