Chapter 9 Flashcards
Covalent vs ionic bonds vs metallic bonding?
Ionic- metal and nonmetal transfer electrons
Covalent- non metal and non metal sharing electrons
Metallic- metal and metal where electrons are polled
What does the amount of valence electrons have to do with an atoms stability?
Full octet=very stable
How do you draw the Lewis symbols for ionic bonds? KCl?
Take the metal and transfer the electrons to the non metal to make a full octext and add a negative charge to the non metal and a positive charge to the metal
K+[Cl]- (has full octet around Cl)
What bond is the strongest? Single, double or triple? Which one is the shortest?
Triple bond is the strongest and shortest
What do δ+and δ- minus mean?
Partial positive and negative charge of atoms that show they are unequally shared in bonds
What is a polar bond?
Having a positive pole and a negative pole
What is the electronegativity of fluorine?
4.0 (the highest)
What does the electronegativity difference between bonded atoms have to do with the polarity of the bond?
The greater the electronegativity difference, the more polar the bond is
What is a covalent bond and it’s electronegativity difference?
Non metal and non metal
Small (0.0-0.4)
What is a polar covalent bond and what is it’s electronegativity difference?
An intermediate in nature between pure covalent and ionic bonds
Intermediate (0.4-2.0)
What is an ionic bond and what is it’s electronegativity difference?
Metal and non metal
Large (2.0-4.0)
How do you pick the central atom in the Lewis diagrams?
The least electronegative element (francium would be the least electronegative)
How do you draw resonance structures?
Put one structure with one bond then put a double header arrow and the same structure with the bond on the other element
What is formal charge?
A fictitious charge assigned to each atom that shows the charge an atom would have shared equally between bonded atoms
What elements disobeys the octet rule and how?
Boron does because in some cases it can only have 6 valence electrons
What is bond energy?
The energy required to break 1 mole of the bond in the gas phase
The stronger the bond, the more chemically stable and less chemically reactive
What is endothermic in terms of bond formation?
Breaking bonds (positive bond energy)
When strong bonds break and weak bonds form
What is exothermic in terms of bond formation?
Forming bonds (negative bond energy)
When weak bonds break and strong bonds form
How to we find the change in enthalpy of a reaction using bond energies?
ΔΗrxn=Σ(bonds broken) + Σ(bonds formed)
Bonds broken is positive
Bonds formed is negative
What does the electron sea model of metallic bonds have to do with them being good conductors of electricity?
The electrons are free to move in response to an electric potential and generate an electric current
How to find smallest or largest dipole moment when given a list of compounds?
Smallest will have the two closest elements (least electronegativity difference)
Largest will have the two furthest elements (largest electronegativity difference)
What does VSEPR stand for? What does it state?
Valence shell electron pair repulsion theory
States that electrons that make bonds try to get as far as possible from eachother
What are the two groups of VSEPR?
Electron geometry- geometry of all electron groups around an atom
Molecular geometry- the geometry of bonding electrons groups only
