Structure 3 Flashcards
(24 cards)
atomic radius
half the distance between the nuclei of two neighbouring atoms of the same element bonded together by a covalent bond
electronegativity
measure of the ability of its atoms to attract electrons in a covalent bond
noble gases
- don’t form bonds to the distance between neighbouring atoms is not defined
- outermost shells competely full
alkali metals
- good conductors of heat and electricity
- low density
- shiny
- reactive
- form ionic compounds
alkali metal + water —> hydrogen + metal hydroxide
halogens
exist as diatomic molecules
- coloured
- gradual change from gases (F and Cl), to liquids (Br), to solids (I and At)
- reactive but reactivity decreases down group
- ionic compounds with metals and covalent compounds with other non metals
displacement reaction
adding solution with halide to solution with silver ions, will create a precipitate
Basic oxide
- dissolve in water to form alkaline solution
- reacts with acid to form water and salt
Metal oxide
- when dissolved in water, forms metal hydroxide
- basic
- ionic compound
- giant ionic structure
- high electrical conduction
Non metal oxides
- acidic
- react with water to form acidic solutions
- molecular covalent compounds
- molecular covalent structure
- low electrical conductivity to none
Amphoteric oxide
- does not affect pH in water because it is basically insoluble
- AO + acid forms salt and water
- AO + base form salt and water
Eg: Al2O3, zinc oxide
Acid rain
sulphuric acid - SO3 + H2O
sulphurous acid - SO2 + H2O
nitric acid (H2NO3) - NO2 + H2O
electron repulsion
makes it easier to remove electron
Zinc not a transition metal
- doesn’t make colored compounds
- not magnetic
- exists only in +2 oxidation state in compounds because it has filled energy levels.
transition metal properties
- high electrical and thermal conductivity
- high melting point
- malleable
- high tensile strength
- ductile
- iron, cobalt and nickel are ferromagnetic
- form compounds with more than one oxidation state (oxidation states above +3 usually show covalent character)
- form variety of complex ions
- form colored compounds
- act as catalysts
magnetism in transition metals
due to unpaired electrons in d orbitals
opposite spins cancel out = no magnetism due to no net magnetic effect
complex ion
- formed when a central ion is surrounded by molecules or ions which possess a lone pair of electrons.
- these surrounding species (ligands) are attached via a coordination bond (dative bond).
- no of coordination bonds from the ligands to the central ion is called the coordination number
coordination bond
a bond in which both shared electrons are supplied by one species
ligand
species that uses a lone pair of electrons to form a coordination bond with a metal ion.
d orbital splitting (color)
1) repulsion between metal ion and ligands makes orbital split into two different levels
2) when ligand approaches a transition element, the lone pairs of electrons on the ligand cause the d orbitals of the transition element to split into two sublevels
3) when light passes through the solution , electrons can be excited to the higher energy sublevel
4) the d orbitals in an isolated transition metal all have the same energy and are said to be degenerate
5) light energy is absorbed to move electrons from low to high level
6) if it absorbs wavelength of one color, it will be the color of its complementary color.
monodentate ligand
- contain a single donor atom and have one lone pair contributing to the coordinate bond in a complex ion
polydentate ligand
- ligands which don’t have two or more donor atoms that form coordinate bonds with a transition metal center
ethylenediaminetetraacetate (EDTA)
- polydentate ligand can form upto 6 coordinate bonds
- hexadentate ligand
- 4 oxygen and 2 nitrogen centers
- used to treat lead poisoning
- used in heart by-passing surgery
- replaces metal ions that cause rancidity, bad odor, tast, or smell in foods (food preservation)
why there’s color change
- difference in color because of an oxidation number
- different ligand - if approaching ligand is stronger, than the split is bigger
- different transition metal (difference in nuclear charge)
spectrophotometry is a method used to determine concentration of colored ions in a solution
absorbance of light depends on concentration of metal ions
functional group trends
boiling point increases with carbon number - increases instantaneous and induce dipole dipole
- volatility
structural isomer
same molecular formula, different arrangement of atoms
