electrons and bonding- chapter 5 Flashcards
what is the principal quantum number
the shell number or energy level number
what is an atomic orbital
a region around the nucleus that can hold up to two electrons, with opposite spins
what are the 4 types of orbitals
s- p- d- f-
describe an s-orbital
the electron cloud is within the shape of a sphere
can hold one or two electrons involved in
each shell from n=1 contains one s-orbital
the greater the shell number n, the greater the radius of its s-orbital
describe a p-orbital
the electron cloud is within the shape of a dumb-bell
can only contain one or two electrons
are three separate p-orbitals at right angles to one another
each shell n=2 contains three p-orbitals
the greater the shell number n, the further the p-orbital from the nucleus
describe d- and f- orbitals
each shell from n=3 contains 5 d-orbitals
each shell from n=4 contains 7 f-orbitals
what are sub-shells
orbitals of the same type are grouped together as sub shells
why must the two electrons have opposite spins in each orbital
helps to counteract the repulsion between the negative charges of the two electrons
what 3 blocks are the periodic able divided into
s-block
p-block
d-block
define ionic bonding
the electrostatics attraction between positive and negative ions. holds together cations and anions in ionic compounds
what are common anions
non-metal ions
polyatomic ions
what are common cations
metal ions
ammonium ions
what do the simplest ionic compounds contain
metal ions and non-metal ions
what structure do ionic compounds make and why
a giant ionic lattice containing billions of ions
each ion attracts oppositely charged ions in all directions, and each ion is surrounded by oppositely charged ions from a giant ionic lattice
explain the feature of melting and boiling points in ionic compounds
-almost all are solids at RT
-at RT there’s insufficient energy to overcome the strong electrostatic forces of attraction between the oppositely charged ions in the giant ionic lattice
-high temp is needed to provide the large quantity of energy to overcome the electrostatic forces between ions
-almost all have HIGH melting and boiling points in
-melting points are higher for lattices containing ions with greater ionic charges as there’s stronger attraction between ions
explain the feature of solubility in ionic compounds
and what 2 processes does solubility require
-many dissolve in polar solvents such as water
-polar water molecules break down the lattice and surround each ion in solution
-the solubility in water may depend on the relative strengths of the attractions within the giant ionic lattice and the attractions between ion and water molecules
-in a compound made of ions with large charges the ionic attraction may be too strong for water to break down the lattice structure so the compound wont be very soluble
- ionic lattice must be broken down
- water molecules must attract and surround the ions
explain the feature of electrical conductivity in ionic compounds
explain in a solid and liquid/dissolved water state
-in solid state and ionic compounds does not conduct electricity but once melted or dissolved in water, the ionic compound does conduct electricity
-solid= ions are in a fixed position in the giant ionic lattice, no mobile charge carries, NON-CONDUCTOR
-liquid= solid ionic lattice breaks down, ions are not free to move as mobile charge carriers, CONDUCTOR
what are the 3 properties of ionic compounds
-high melting and boiling point
-tend to dissolve in polar molecules such as water
-conduct electricity only in the liquid state or in an aqueous solution
what is covalent bonding
the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
where does covalent bonding occur (3)
non metallic elements
compounds of non metallic elements
polyatomic ions
what is covalent bonding in terms of overlap
the overlap of atomic orbitals, each containing one electron, to give a shared pair of electrons
-the shared pair of electrons is attracted to the nuclei of both the bonding atoms
-the bonded atoms often have outer shells with the same electron structure as the nearest noble gas
why is the covalent bonding very different
the attraction is localised, acting solely between the shared pair of electrons and the nuclei of the two bonded atoms
what does the displayed formula show
the relative positioning of atoms and the bonds bonds between them as lines
what are lone pairs
paired electrons that are not shared
what is a double bond
the electrostatic attraction between two shared pairs of electrons and the nuclei of the bonding atoms
what is a triple bond
the electrostatic attraction between three shared pairs of electrons and the nuclei of bonding atoms
what is a dative covalent/coordinate bond
a covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only
in a dative covalent bond the shared pair was originally a lone pair of electrons on one of the bonded atoms
what is the average bond enthalpy
a measurement of covalent bond strength
the larger the value of average bond enthalpy, the stronger the covalent bond
