Bonding Flashcards
When an atom gains or loses an electron they are called…
ions.
Metals form what type of ion?
Positive (cation)
Non metals form what type of ion?
Negative (anion)
What group or groups do not form ions?
4 n 8
Transition metals can form many different ions and are usually distinguishable by….
COLOR
What is a lattice structure???
They are the 3D shape that ionic compounds take one. When talking about ionic compounds try to avoid the word “molecule” because they don’t form molecules they form a lattice. LATTICE. say it. three times. sounds like lettuce
Describe a covalent bond
- between two nonmetals.
- two atoms share electrons. how sweet
- a group of covalent bonds forms a MOLECULE. this is a molecule. covalent bond means molecule. yay
Compare and contrast double and triple bonds.
Double bonds have one sigma and one pi bond. Triple have one sigma and two pi bonds. Triple bonds are also stronger and shorter than double bonds.
What are dative compounds?
Covalently bonded molecules that are stable but do not follow the octet rule. They react with compounds that have a lone pair (such as H20 or NH3). Examples of dative compounds are BeCl2 and BF3.
Describe a polar bond.
This occurs when there is a difference in the electronegativities of bonded atoms. The more electronegative atom pulls the electrons closer to itself creating a polarity.
What is the VSEPR theory?
Valence Shell Electron Pair Repulsion. That the shape of a molecule is determined by the repulsion between electron pairs in the outer orbital.
Significance of lone pairs (non-bonding pairs of electrons) with regards to the VSEPR theory.
Lone pairs have a higher concentration of charge than a bonding pair and cause more repulsion. Molecules with lone pairs on the central atom have some distortions in their structure which reduce the angle between the bonded angles.
Shape and bond angle of molecules with two negative charge centers.
Linear. Bond angle is 180.
Shape and bond angle of molecules with three negative charge centers.
Triangular planar, 120
Shape and bond angle of molecules with three negative charge centers, but one of the charge centers is a lone pair.
Bent, 117
Shape and bond angle of molecules with four negative charge centers.
Tetrahedral, 109.5
Shape and bond angle of molecules with four negative charge centers, but one of the charge centers is a lone pair.
Trigonal Pyramidal, 107
Shape and bond angle of molecules with four negative charge centers, but two of the charge centers is a lone pair.
Bent, 105
Is it possible to have polar bonds within a non-polar molecule.
Yes. Just yes.
True or false: some covalent substances form crystalline solids.
True.
Describe the crystalline substance.
A single molecule that ha a regular repeating pattern of covalent bonds. Referred to as a giant molecular or MACROMOLECULE.
What is an allotrope?
A different for or forms of an element in the same physical state. The different forms are due to different bondings within the structures that result in different shapes and properties.
What are the three carbon allotropes.
Graphite
Diamond
Fullerene
Describe graphite as an allotrope of carbon.
Each C atom is linked to three more. Forms a hexagons with 120 bond angles. Parallel layers are held by van der waals forces.
Has one delocalized, non bonded electron. Because of that electron it can conduct electricity.
Looks: Dull, gray and solid.
Uses: Found in pencils. Yeeeh
Describe diamond as an allotrope of carbon.
Each C atom is covalently bonded to 4 others. They are tetrahedrally arranged in a regularly repetitive pattern of 109.5 bond angles. Hardest known material in existence.
All the electrons are bonded. Since there are no floating electrons it cannot conduct electricity.
Looks: It is shiny. But seriously. You know what a diamond looks like. Don’t be dumb.
Uses: jewelry, glass cutter.
Describe Fullerene as an allotrope of carbon.
Sphere of 60 carbon atoms. Consists of 12 pentagons and 20 hexagons. Each carbon is bonded to three others.
Easily accepts electrons to form negative ions. It is a semiconductor at normal temperature and pressure.
Looks: YELLOW crystalline solidl soluble in benzene.
Uses: reacts with K to make a super conductor; nanotubes can be made for electronics; catalysts
Compare Silicon and silicon dioxide.
Silicon: each silicon atom is covalently bonded to four more. tetrahedral arrangement. Giant lattice structure similar to a diamond.
Silicon dioxide: known as silicia or quartz. Forms a giant covalent structure. Si and O are bonded in a tetrahedral shape. Each Si is bonded to 4 O atoms. Each O atom is bonded to 2 Si. It is insoluble in water, does not conduct anything. Different forms are sand and glass.
What is an INTERmolecular force? Give three examples.
Forces that exist BETWEEN molecules.
Van der Waals’ forces
Dipole-Dipole attraction
Hydrogen Bonding
Describe Van der Waals forces
Temporary dipoles form in molecules due to the ever changing electron density. Van der Waals is the attraction between opposite ends of two temporary dipole molecules. Generally, they are weak and easily broken thus molecules with VWF have Low melting points and boiling points.
Increasing number of electrons and molecular size will increase the chance of a temporary dipole and the VWF. (larger mass = stronger VFW = higher boiling point)
Describe a dipole-dipole attraction.
Typically occurs between molecules that have polar bonds. The delta negative end of one molecule is attracted to the delta positive end of another molecule.
Strength varies depending on the degree of polarity
Describe hydrogen bonding.
When a molecule containing hydrogen is covalently bonded to FON of another molecules. This bond is a SUPER STRONG dipole dipole attraction. It’s so strong it gets its own mf name. Though strong, they are weaker than intramolecular forces such as covalent and ionic bonds.
Need a super high boiling point to break.
Water is a perf example.
What are delocalized electrons? When are they present?
Delocalized electrons are present in the elemental state of a metal. The outer electrons are “loose” and begin to wander through the metal structure. After losing the electron the atom becomes a positive ion and connect with the neighboring positive ions to form a lattice structure. The electrons then move freely through this structure and are able to conduct electricity.
The delocalized electrons are able to move any which way. This allows the metal to be malleable (able to be shaped) and ductile (can be drawn into threads).
Compare and contrast the boiling and melting points of ionic compounds and covalent compounds.
Ionic compounds = high
Giant covalent structures = high
Covalent = low
Compare and contrast ionic compounds, polar covalent compounds, and non-polar covalent compounds with regard to their solubility in polar solvents and non polar solvents.
Ionic compounds = Soluble in polar, not soluble in non polar.
Polar Covalent = solubility increases as polarity increases; solubility increases as polarity decreases.
Non-polar covalent - not soluble in polar solvent; soluble in non polar.
Compare and contrast ionic compounds, polar covalent compounds, and non-polar covalent compounds with regard to conductivity.
Ionic= As a solid they cannot; in the liquid and molten states they are able
Polar = some of them can give n right circumstances (ie HCL in water)
NPC = cannot conduct
