electrons and bonding chp 5 Flashcards
(42 cards)
what are shells
-shells are regarded as energy levels
-the energy increases as the shell number increases
-the shell number or energy level number is called the principal quantum number (n)
how many electrons are able to occupie the shell 1-4
what is the formula for calculating the number of electrons in each shell
2n^2
what is an atomic orbital
- a region around a nucleus that can hold up to 2 electrons
what make up the shells
shells are made up of sub shells which themselves are made up of atomic orbitals
each new shell gains a new type of sub shell and therefore orbital
what are the features of an s-orbital
-the shape of a sphere
-each shell from n=1 contains 1 s-orbital
-the greater the shell number (n), the greater the radius of its s-orbital
what are the features of a p-orbital
-the electron cloud is within the shape of a dumb-bell
-one orbital can contain 1 or 2 electrons
-there are 3 separate p-orbitals at right angles to one another (these orbitals are referred to as px,py and pz
-each shell from n=2 contains 3 p-orbitals
-the greater the shell number n, the further the p-orbital is from the nucleus
what are the features of the d and f orbtials
-each shell from n=3 contains 5 d-orbitals
-each shell from n=4 contains 7 f-orbitals
what is a sub-shell
- orbitals of the same type are grouped together as sub-shells to produce shells
table
how does the presence of sub-shells effect the number of electrons within a shell
how do orbtials fill
orbitals fill in order of increasing energy
why do electrons in the same orbitals spin oppositly to eachother
- helps to mitigate the repulsion between the like charges, within an orbital
How are orbitals of the same energy filled
-within a sub-shell, one electron occupies each orbital before pairing up starts, this prevents any repulsion between paired electrons until there is no further orbital available at the same energy level
what does the electron configuration show
shows how sub-shells are occupied by electrons
how would you write a shorthand configuration
the short hand is shown in terms of the previous noble gas plus the outer electron sub-shells of the element your illustrating
what do the blocks of the peridoic table tell us
s-block, highest energy electrons in the s-sub-shell
P-block, highest energy electrons found in the p-sub-shell
D-block, highest energy electrons in the d-sub-shell
how does ionisation effect the electron configuration
the highest energy sub-shells lose or gain electrons
whats unique about the 4s and 3d sub-shells
- 4s sub-shells fill and empty before filling and emptying of 3d sub-shelled
- as is at a lower energy level
what is ionic bonding
- electrostatic attraction between positive and negative ions
describe how to produce a dot and cross diagram for a ionic compound
- electrons from the oxidising atoms are shown as either cross or dots
- Show the outer shell of both ions with the electrons
- use square brackets to show charge is over whole ion
- show the charge of the ion just outside square brackets
what is the structure of an ionic compound and what causes this
ionic compounds form giant ionic lattices due to the fact that an ion attracts oppositely charged ions in all directions
what is the boiling and melting point of ionic lattices and how is it explained
-Almost all ionic compounds are solid and room temperature
-High temperatures are needed to provide the energy needed to overcome the electrostatic forces, therefore most ionic compounds have high melting and boiling points.
how does the individual charge of an ion effect the ionic compounds melitng and boling point
the melting points are higher for lattices containing ions with greater ionic charges, as there is stronger attraction between ions
Are ionic compounds soluble
many ionic compounds dissolve in polar solvents, such as water, by breaking down the lattice and surrounding each ion.
