Chem bonding and structures of matter Flashcards
Bonding present in a Ionic Compound?
Strong electrostatic forces of attraction hold positive ions and negative ions together to form a giant lattice structure
mistake: no ionic crystal
Structure of Ionic bonds
Giant Ionic Crystal Lattice Structure
Volatility of a ionic compound
High melting and boiling point.
Large amount of energy needed to overcome strong electrostatic forces of attraction present between ions in the giant lattice structure
State of ionic compounds
Solids at room temperature
Why? high volatility
Solubility of ionic compounds
Soluble in water (polar solvents) , but not in organic compounds.
Type of attraction in ionic compounds similar to that of water, but not in organic solvents.
Electrical Conductivity of ionic compound 💕
In solid:
Ions are held together in fixed position in a giant ionic crystal lattice structure
In liquid:
Strong electrostatic forces of attraction (BONDS) between ions are broken down (completely), ions can move freely (mobile) and conduct electricity.
Bonds of a covalent compound (SMS)
Simple discrete molecules held together by strong electrostatic forces of attraction between positively-charged nucleus and negatively-charged shared pair of electrons
*common mistake: muss diff btw gms i.e simple discrete molecules NOT atoms
Bonds present btw atoms vs bonds present btw molecule (SMS)
Each atom is held together by strong electrostatic forces of attraction»_space; large amount of energy needed to overcome
Note: higher bp tk do this (i.e atomization)
structure of the covalent compounds
simple molecular structure
Volatility for Covalent Compound (SMS)
Small amount of energy is needed to overcome weak intermolecular forces of attraction btw molecules, thus, there there is a lower bp/mp
state of the covalent compound at r.t.p (SMS)
exist as liquid/gas at r.t.p»_space;low mp/bp
Solubility of Covalent Compounds (SMS)
Soluble in organic solvents and NOT polar solvents
Electrical conductivity of Simple Molecular Structure
Cannot conduct electricity in ANY STATE as SMS made of molecules which do not carry any charge, thus cannot conduct electricity due to the absence of mobile CHARGE carriers.
*mistake: charge
Bonding present in Covalent Compound (GMS)
EXTENSIVE NETWORK OF atoms held together by strong electrostatic forces of attraction btw positively charged nucleus and negatively-charged shared pair of electrons.
Volatility of Covalent Compound (GMS)
Large amount of energy needed to break apart strong efoa btw positively charged electrons and negatively charged shared pair of electrons
*just covalent bonds can too
Structure of a Giant Molecular Structure
Giant Molecular Structure
- Tetrahedrial Structure
Large nom of strong cov bonds present throughout extensive network structure
(each C atom bonded to 4 other C atom)
Diamond, Silicon Dioxide
2. Hexonigal Structure
Layers of atoms slip and slide over one another due to presence of weak IMFOA
Graphite
(each c atom bonded to 3 other C atoms)
MELTING point of graphite VS diamond
diamond has tetrahedrial structure. large no. of strong cov bonds throughout large extensive network structure. Greater amoumt of energy needed to overcome cov bonds
graphite has a hexonigal structure, presence of weak imfoa btw layers of carbon atom, this causes CARBON atoms to slide over one another
Less energy needed to overcome weak IMFOA
State and Texture of GMS
Solid at r.t.p
- Graphite : layers of carbon atoms slip and slide over one another»_space; soft and slippery
- Diamond : large no. of strong cov bonds present throughout extensive network structure》》 rigid》》hard and strong
Solubility of GMS
Insoluble in every solvent
Electrical Conductivity of GMS
- Diamond (tetrahedrial)
each C atom bond to 4 other C atoms via via single c-c cov bond, thus all of valence electrons involved in bonding, unable to conduct electricity due to absence of mobile charge carriers
Graphite (hexonigal) :
Each C atom is bondes to 3 other C atoms via ssingle c-c cov bonds, presence of one valence electron per carbon atom, thus able to conduct elec along the layers of graphite.
note: each layer=1 molecule
Bonding in a metal compound
Strong efoa btw positively charged metal atoms and negatively charged sea of delocalized electrons.
Structure of metal compounds
Giant Metallic Lattice Structure
Volatility of metal compounds
Large amount of energy needed to break strong efoa btw + charged metal atoms (cations) and - charged sea of delocalized electrons (metallic bonds)
Solubility of metal compounds
Insoluble in any solvent
Electrical conductivity of metal compounds
can conduct elec in all states due to presencd delocalized electrons which act as mobile charge carriers to conduct elec from + terminal of source and move btw the catio s in the metallic structure
Malleability (bends easily)and Ductility (easily pulled thru wires) of metallic compounds
When valence elec of an atom delocalize, dont belong to any atom> metal atoms are similarly sized and arranged in regular layers. if force applied = layer of metal atoms slide thru each other (thru delocalized e-) w/o disrupting the metal lattice
What is electronegativity?
Measure of the tendency of an atom to attract a bonding pair of electrons
What affects erectronegativity?
Higher number of proton in nucleus: stronger electronegativity
Smaller distance of shared electrons from nucleus : stronger electronegativity
little shielding effect by inner electrons: stronger electronegativity
What if equal electronegativity?
Same tendency to attract bonding pair of electrons: found ave-halfway btw 2 atoms
only for same element: diatomic( ie. H2 02)
Pure covalent bond
It B is slightly more electronegative than A
Element has more than its fair share of electron density : more electronegative
Pulls electron towards nucleus has slightly negative charge:
Other elements is much less electronegative: cannot hold onto electrons as well: slightly positive charge
Electron pair dragged over to b
What affects bonding in ionic compound
- Size of ion
Size of ion decreases: ionic radii decreases: decrease strength of electrostatic forces attraction between positive and negative ions: less energy needed to overcome strong ionic bonds: decrease melting point - lonic charge
Electrostatic forces of attraction between decrease energy positive ion and negative ions decreased : decrease energy needed to overcome strong ionic bonds present btw ions in the ionic compound= decrease melting boiling point
What affects bonding in a covalent substances
Bond Size/ molecule:
bonding btw molecules- intermolecular forces of attraction
Increase bond size= stronger intermolecular forces of attraction btw molecules = more energy needed to overcome imfoa= higher bond/map
Bond length:
Bonding btw each atom in a molecule
CoV bonds
If no. Of electron shells decrease= decrease distance btw positively charged nucleus and negatively chaired shared pair of electrons= stronger cov bonds = more energy needed
Bond energy:
Atoms of a molecule
CoV bonds
Greater bond energy= stronger CoV bonds= increase energy needed
What is bond length
Average distance btw nuclei of 2 CoV bonded atoms of a molecule
What is bond energy.?
Amount of energy needed to overcome bonds btw one mol of CoV bonded gas
Vibrate until atoms are energetic enough to overcome strong CoV bonds btw positively charged nuclei and negatively charged shared pair of electrons
What affects bonding-in a metallic compound.
- No. Of valence electrons
Increase number of valence electrons = no. Of valence electrons lost to form cations = increase no of delocalized electrons in the metallic lattice structure = more energy needed to overcome strong electrostatic forces of attraction btw positively charged metal cation and sea of delocalized electrons ( METALLIC BONDS) = higher mp/ bp - Electron shells
If no.of electron shells increase= distance btw positively charged metal cation and sea of delocalized electrons increase= decrease strength of metallic bonds = less energy needed to overcome efoa btw + charged cation and - charged sea of delocalized electrons ( METALLIC BONDS) = higher mp/ bp
