C7-Organic chemistry Flashcards
(37 cards)
Properties of Metals
HIGH DENSITY: The metals ions tightly packed.
HIGH MELTING POINT: A large amount of thermal energy is required to overcome the strong metallic bonds holding the crystal together.
ELECTRICAL CONDUCTORS: The delocalized electrons are able to move within the metallic lattice.
THERMAL CNODUCTORS: the delocalized electrons transmit the energy of vibration from one ion to its neighbours
MALLEABLE AND DUCTILE: The metal ions can slide past each other without disrupting the metallic bonding
LUSTROUS: The free electrons causes most metals to be excellent reflectors of visible light. They are shiny.
Other properties of Metals
Strong
react to form positive ions (cations)
Combine with non-metallic elements to form ionic compounds
mix with other metallic elements to form alloys
Chemical properties of Metals
Metals react by losing valence electrons to form positive ions or cations.
Metals that tend to lose their electrons very readily are highly reactive metals. e.g. Na, K, Ca
Metals that do not tend to lose their electrons readily are unreactive or “noble” metals
e.g Ag, Au, Pt.
Bonding
Atoms chemically combine (bond) by one of two processes:
The loss and gain of electrons (described as ionic bonding)
Combing atoms share electrons (described as COVALENT BONDING)
IOnic Bondign
Ionic bonding occurs when metals chemically combine with Nonmetals
Metals lose electrons to become cation (positive).
Non-metals gain electrons to become anions (negative).
(How can you tell how many electrons an element will lose or gain).
The cations are attracted to the anions by electrostatic interactions.
The overall charge of an ionic compound must equal zero
Ionic compound def
Ionic lattice is a repeating 3D arrangement of ions
Ionic compounds properties
High melting/ boiling points- Ionic bonds involve strong electrical attractions between oppositley charged ions and thus require a large amount of thermal energy to be broken
Britle (ionic compounds)
Under a shearing force ions of the same charge come closer and their repulsion causes the crystal to shatter
Covalent Bonds
covalent bond, in chemistry, the interatomic linkage that results from the SHARING OF AN ELECTRON PAIR BETWEEN TWO ATOMS.
Ionic Bond
Ionic bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.
Metallic bonding
Metallic bonding is a type of chemical bonding that occurs between metal atoms, where electrons are not bound to individual atoms but are instead delocalised and free to move throughout a lattice of positive metal ions. This “sea of electrons” allows metals to conduct electricity and heat, and gives them properties like malleability and ductility.
Covelent Network substances
The whole crystal is one ‘giant’ macromolecule held together by a continuous linkage of strong covalent bonds
Covalent Network structure
Allotropes
are different structures of an element. The atoms of the element are bonded together in a different manner.
allotropes of carbon: diamond, graphite, fullerenes
The have different physical properties.
hydrogen bond
A weak attraction between a hydrogen atom (bonded to N, O, or F) and a lone pair on another electronegative atom.
Type: Intermolecular force
Strength: Stronger than dispersion & dipole-dipole, weaker than covalent bonds
Common in: Water, DNA base pairs, alcohols
Importance: Affects boiling points, solubility, and structure of molecules
diploids
Naming organic chemistry
why does metal have high melting points?
A dipole occurs when there is a separation of positive and negative charge in a molecule due to differences in electronegativity.
Permanent Dipole: Caused by polar covalent bonds
Molecular Dipole: Depends on shape — if dipoles don’t cancel, molecule is polar
Symbol: δ⁺ and δ⁻
Leads to: Dipole–dipole interactions (intermolecular force)
why do ionic compounds have high melting points
Ionic compounds have high melting points because the strong electrostatic attraction between oppositely charged ions in the lattice requires a large amount of energy to overcome. This makes it difficult for the ions to move apart, so the substance stays solid until very high temperatures.
intermolecular bonding
Intermolecular bonding refers to the forces of attraction between separate molecules. These forces are weaker than covalent or ionic bonds but play a key role in determining physical properties like boiling and melting points. Types include dispersion forces, dipole-dipole interactions, and hydrogen bonding.
what are the physical properties of covalent network solids
What are the physical properties of covalent network solids?
- Very high melting and boiling points due to strong covalent bonds throughout the structure
- Hard and rigid but brittle
- Usually poor conductors of electricity (graphite is an exception)
- Insoluble in water and most solvents
3 common covalent networks
What are 3 common covalent network solids?
Diamond: very hard, tetrahedral structure, excellent thermal conductor
Graphite: layered structure, conducts electricity, slippery
Silicon dioxide (quartz): rigid 3D network, very hard, high melting point
what is a lattice and where is it found
What is a lattice and where is it found?
Back:
A lattice is a regular, repeating 3D arrangement of atoms, ions, or molecules
Found in crystalline solids such as ionic compounds, metals, and covalent network solids
Determines the solid’s structure and influences properties like melting point and hardness
what is a hydrogen bond and why does it form
A hydrogen bond is a weak attraction between a hydrogen atom, which is covalently bonded to a highly electronegative atom like nitrogen, oxygen, or fluorine, and a lone pair of electrons on another electronegative atom.
It forms because the electronegative atom pulls electron density away from hydrogen, giving it a partial positive charge that is attracted to lone pairs nearby.
