Topic 4 - Chemical bonding Flashcards
How are ions formed?
- when one or more electrons are transferred from one atom to another
What is an ionic bond?
- the electrostatic attraction experienced between the electric charges of a cation and an anion
- build up into a strong lattice
What is oxidation?
- loss of electrons
- gain of oxygen
What is reduction?
- gain of electrons
- loss of oxygen
Between what are ionic compounds generally formed by?
- metals and non-metals
What is the octet rule?
- elements tend to lose electrons (oxidation), gain electrons (reduction) or share electrons to acquire a noble gas core electron configuration
What is volatility?
- the tendency of a substance to vaporise
How are the boiling and melting points of ionic compounds and why?
- high
- strong electrostatic attractions between ions
- large input of energy needed to break apart the forces
How is the volatility of ionic compounds and why?
- low
- electrostatic forces of attraction are very strong
How is the electrical conductivity of ionic compounds and why?
- good electrical conductor when molten
- ions cannot move in a lattice structure (do not conduct)
- ions are free to move in a molten state (conduct?
How is the solubility of ionic compounds and why?
- dissolve in polar solvents
- do not dissolve in non-polar solvents
How are covalent bonds formed?
- an electrostatic attraction between the shared pair of electrons and the positively shared nuclei
What kind of region is a covalent bond?
- relatively high electron density between nuclei that arises at least partly from the sharing of electrons and gives rise to an attractive force and characteristic internuclear distance
Between what are covalent compounds generally formed by?
- non-metals
What is the Lewis electron dot structure?
- simple method of representing the valence electrons of an element
- each element is surrounded by a number of dots/crosses that represent the valence electrons
How are the boiling and melting points of covalent compounds?
- low
How is the volatility of covalent compounds?
- can be
How is the electrical conductivity of covalent compounds and why?
- do not conduct
- there are no ions to carry the charge
How is the solubility of covalent compounds?
- typically insoluble
How is a polar covalent bond formed?
- when one has a greater attraction - one atom has a partial negative charge and the other a partial positive charge