Chapter 3 Flashcards
What are chemical bonds?
forces that hold atoms together
What will atoms aim to do as they bond?
position themselves to reduce/minimize their overall energy by filling their outer shell
What are the types of chemical bonds?
ionic, nonpolar covalent, and polar covalent
What is electronegativity?
atom’s ability to attract electrons to itself
If the electronegativity difference is less than 0.4, what type of bond is it?
nonpolar covalent
if the electronegativity difference is between 0.4 to 1.7, what type of bond is it?
polar covalent
If the electronegativity difference is greater than 1.7, then what type of bond is it?
ionic
When does ionic bonding happen?
forms between oppositely charged ions with metals and nonmetals
What is the “formula unit” ?
NaCl
How is the bonding strength for ionic compounds?
it is very strong and they are not easy to separate
How is the melting point for ionic compounds?
the melting point is very high
How is the conductivity of electricity for ionic compounds?
low as solids and high when dissolved in water or melted
What is bond energy?
measure of chemical’s bond strength
in the bond energy equation, what does E represent?
energy in joules
In the bond energy equation, what does r represent?
distance from ions in nm
In the bond energy equation, what does Q1 and Q2 represent?
charges of the ions
What do atoms seek to do in terms of configuration?
they seek to do a noble gas configuration
In group 1A, do atoms lose or gain electrons?
they lose 1 electron
In Group 2A, do atoms lose or gain electrons?
they lose 2 electrons
In group 3A, do atoms lose or gain electrons?
they lose 3 electrons
In Group 6A, do atoms lose or gain electrons?
they gain 2 electrons
In group 7A, do atoms lose or gain electrons?
they gain 1 electrons
When predicting the formulas for ionic compounds, what must you consider?
1) consider a number of valence electrons for both atoms
2) consider atom’s electronegativity (non-metals are more electronegative)
3) chemical compounds are always electrically neutral
What is covalent bonding?
when electrons are shared between atoms
Why do covalent bonds happen?
if the energy of the electrons in hydrogens are lower, for example, they tend to share since the electrons are attracted towards a positive charge
What does — represent in bonding?
sharing of electrons
What is the bond length?
distance between two atoms where energy is lowest (aka smallest distance) and it happens with two or more NON-METALS
What is the bond strength of covalent compounds?
weaker and requires less energy to break
How is the melting point for covalent compounds?
low melting point (like sugar)
How is the conductivity of covalent compounds?
very poor and poor in water as well
What are polar covalent bonds?
when there is an unequal sharing between atoms in a molecule and they is not enough energy to split
The more electronegative atom in a polar covalent bond has what partial charge?
negative
The less electronegative atom in a polar covalent bond has what partial charge?
positive
What is the driving force for bonding?
energy
What is the localized electron model?
assumes that molecules are composed of atoms that are bound together by sharing pairs of electrons
What are lone pairs?
electrons that are localized on an atom, usually in two pairs
What is a bonding pair?
electrons found in the space between the atoms in a bond
What are the parts of the localized electron model?
a) using Lewis structures to describe valence electrons only in an arrangement in the molecule
b) using VESR to predict the geometry of molecules (in the 4th chapter)
c) describing orbitals used by atoms to share electrons or hold lone pairs
For Lewis Dot Structures, what is the main goal?
atoms achieving noble gas configurations
