electrons and bonding Flashcards
what are shells
-energy levels
-energy increases as shell number increases
what is the principal quantum number
- the shell number or energy level number
- the further a shell from the nucleus the higher its principal quantum number
why do shells have sub shells
- all electrons in a shell dont have the same energy
what are orbitals
- a region around the nucleus that can hold up to 2 electrons with opposite spins
- each orbital has a different shape
what shape does an s and p subshell have
- s–> sphere
-p–> 3 dumbbell shaped orbitals at right angles to one another
how many orbitals in each subshell
s–> 1
p–> 3
d–> 5
f–> 7
what is ionic bonding
- electrons are transferred from metal atoms to non metal atoms
- oppositely charged ions bonded by electrostatic force of attraction
-giant ionic lattice
explain the melting points of ionic compounds
-solid at room temp–> room temp doesn’t have enough energy to overcome strong electrostatic forces
- high melting points —> strong electrostatic forces of attraction
-melting points higher for lattices containing ions with greater ionic charges as stronger attraction and for ions with different sizes
explain solubility of ionic compounds
-solubility of ionic compounds decreases as ionic charge increases–> solubility depends on relative strength of attraction in ionic lattices and the attraction between ions and water molecules
how do ionic compounds dissolve
-ionic lattice breaks down
-water molecules surround the ions
explain electrical conductivity in ions
- cannot conduct when solid–> ions in a fixed position in the lattice–> no mobile charge carriers
- can conduct when aqueous –> solid ionic lattice breaks down–> ions free to move as mobile charge carriers
what is covalent bonding
- shared pair of electrons between 2 non metals
- so that each atom has a noble gas arrangement
-covalently bonded atoms held together by electrostatic forces of attraction between nuclei and shared electrons
explain the strengths of covalent bonds
- depends on how much the outer atomic orbitals overlap and how strongly the nuclei are attracted to the shared electrons
- strength of bond can be determined by its bond enthalpy
explain the melting points of covalent molecules
-low melting point
- within molecule is strong covalent bonds but between molecules are weak intermolecular forces
explain conductivity of covalent molecules
-poor conductors
-no charge for particles to carry current
what is the structure of metals
- each atom donated its negative outer shell electrons to a shared pool of electrons
-cations are in a fixed position maintaining the structure of metal
-delocalised electrons mobile
what is metallic bonding
attraction between cations and delocalised electrons
what are giant covalent structures
- billions of atoms held together by a network of strong covalent bonds
- no intermolecular forces
what are properties of giant covalent structures
-very high melting point
-insoluble in almost all solvents–> lattice cannot be broken
-mostly unconducive except for graphite
describe diamond
- 4 carbons covalently bonded together
- tetrahedral arrangement
-hardest substance known
describe graphite
- 3 carbons bonded together in layered structure
-layers made of hexagons with bond angle of 120 - layers held together by intermolecular forces–> slippery
describe silicon oxide
each sillicon shared by 4 oxygens and each oxygen shared by 2 silicons
