Unit 1: Chapter 4 - Bonding Compounds Flashcards
What is the definition of an ionic bond?
The ionic bond is the electrostatic force of attraction between a positively charged metal ion and a negatively charged non-metal ion.
What do ionic compounds form?
Three dimensional structures called lattices.
In each ionic structure what are there equal numbers of and what does this produce?
In each structure there is equal numbers of positive and negative ions to produce the neutral compound. For example NaCl contains a sodium atom for every chlorine atom.
What does the large difference in electronegativities allow to happen in the NaCl compound and what does this mean for the sodium and chlorine atom?
The large difference allows the chlorine atom to completely strip away sodium’s outer electron. This leaves chlorine with a strong negative charge and sodium with a strong positive charge.
What are most covalent compounds formed by?
Most covalent compounds are formed by a combination of non-metallic elements.
What can covalent compounds be in the form of?
Discrete molecules or network structures.
In the discrete molecule form in covalent bonding, What is the main bond?
The main bond is the strong intramolecular covalent bond with the weaker bond being the intermolecular bond of the London Dispersion Forces which has an impact on the properties of the molecule.
When there is little difference in electreronegativities between atoms what is produced?
A pure covalent bond.
When a pure covalent bond is formed what are the electrons in the atom?
equally shared
In the network structure of covalent compounds, is there any effect from London Dispersion Forces?
No
What is the compound made from in the network structure of covalent compounds?
Strong covalent bonds only.
What are are polar covalent bonds?
An unequal sharing of electrons in the covalent bond.
What determines the polar covalent bond?
The electrons moving towards the more electronegative atom.
What does the term “dipole” refer to?
A molecule that carries a slightly positive and slightly negative part.
Why can some molecules carry a permanent dipole?
Due to the unsymmetrical nature of the molecule.
Describe how ammonia is a permanent dipole?
Nitrogen the more electronegative atom pulls the bonding electrons towards itself leaving the molecule with slightly positive and slightly negative poles.
Name two types of symmetric molecules containing dipoles?
Carbon dioxide and tetrachloromethane.
What happens to the dipoles in a symmetrical molecule?
The dipoles cancel each other out. i.e. there is no slightly positive or negative ends.
Do symmetrical molecules containing dipoles have polar covalent properties?
NO!!!
What are at opposite ends of the bonding continuum?
Pure covalent bonding and pure ionic bonding.
Why are pure covalent and pure ionic bonding at opposite ends of the bonding continuum?
Pure ionic bonds have electronegativitie values of around 3 whereas pure covalent has electronegativitie values of around 0.5.
What molecules have greater ionic character?
Molecules with higher electronegativity values.
If there is a larger difference in electronegativities in a molecule what will the bond in the molecule be?
More polar.
If the elcetronegativity is greater between molecule what happens to the electrons and what does this result in?
If the difference is large, then the movement of bonding electrons from the element of lower electronegativity to the element of higher electronegativity is complete, resulting in the formation of ions.
What is an inconsistency in the bonding continuum?
Tin(IV) Chloride, a metal compound which has polar covalent properties.
What are the types of bonding as the electronegativities decrease in the bonding continuum?
Pure/strongly ionic, ionic, polar covalent, covalent ,strongly/pure covalent.
What is the bonding between polar molecules known as?
Permanent Dipole to Permanent Dipole interactions.
Are permanent dipole to permanent dipole interactions stronger than the London dispersion forces?
YES
What are examples of polar molecules?
Ethanol, Trichloromethane and water.