Chapter 5 Electron Sturcture + Ionic Amd Covalemt Bonding And Structure Flashcards
Which shells have a higher energy
The ones further from the nucleus
What is a shell divided into
Sub shells
What is the principle quantum number and how do you find the maximum amount of electrons in a shell
The shell number
2n^2 where n=shell number
What are the rules for each orbital
Shells are made from orbitals
Each one can hold 2 electrons with opposite spins
4 different types s,p,d,f
Characteristics of s orbital
Spherical
From shell one each shell contains one s orbital
The greater the shell number the greater the radius of the s orbital
Contains 2 electrons in each shell
Characteristics of a p orbital
3D dumbbell shape
From shell 2 each shell contains 3 p orbitals at right angles to each other
The max number of p electrons in each shell is 6
D and f orbitals
D- from shell 3 each shell contains 5 d orbitals
Total d electrons is 10
F- from shell 4 each shell contains 7 f orbitals
Total f electrons is 14
Definition of atomic orbital
A region within an atom that can hold up to electrons with opposite spins
Describe what 1s^22s^22p^6 represents
The big numbers represent the shell number
The letters represent the sub shell
The powers represent the number of electrons
Rules for electron configuration
1) electrons fill up the lowest energy sub shells first
2) electrons fill orbitals singularly before adding the second
Exception to electron configuration rules
4S fills up before 3D
An exception to this is chromium and copper
Describe the pattern on the periodic table
The s block is group one and two ( hydrogen and helium are 1s, lithium and beryllium are 2s)
The p block is group 3-0
The d block is the transition metals
What is ionic bonding
Outer shell electron transferred from metal to non metal
Oppositely charged ions formed which are bonded by electrostatic attraction -multidirectional
Define an ionic bond
The electrostatic attraction between oppositely charged ions
What do the numbers in the formula of the ionically bonded substance represent
The ratio of the elements in the giant structure
Structure of ionic compounds
Giant ionic lattice held by electrostatic forces
Each ion attracts oppositely charged ions from each direction
Properties of an ionic substance
- High MP and BP=large amount of energy to break electrostatic forces (the greater the charge on the element the higher the mp and bp)
- Solubility= they dissolve in polar solvents however if the ionic attraction is too strong they can be slightly soluble or insoluble
- electrical conductivity =don’t conduct when solid, ions are fixed, do conduct when molten or aqueous as the ions are free to move and carry charge
What is a covalent bond
Between non metals
Electron pairs occupy space between two atoms nuclei, it is unidirectional
Electrons attracted to both nuclei, this attraction overcomes the repulsion between the two nucleus
Define covalent bond
A bond formed by a shared pair of electrons between two atoms. It is the attraction between the nuclei and the electrons
What three things can atoms form when covalently bonded
Single unit eg H2
Giant covalent structure eg SiO2
Polyatimic ion NH4+
Describe and define a molecule
Consists of a defined number of atoms covalently bonded
Is the smallest part of a covalent compound that can exist while maintaining the chemical properties of the compound
Define lone pair
Is an outer shell pair of electrons that is not involved in chemical bonding
How do you draw a dative bond
Arrow goes away from the atom with the lone pair of electrons
One dot either side of the arrow
Common ions that contain dative bonds
Ammonium ion (NH4+) the H+ ion has no electrons NH3 has a lone pair
Oxonium ion (H3O+)
Define dative covalent or coordinate bond
Shared pair of electrons which has been provided by one of the bonding atoms only
What happens when there aren’t enough electrons to reach an octet (covalent)
Within period 2 this occurs to Be and B
They bond with what they can
Eg BF3
B ended up having 6 electrons in outer shell, missing two
What happens when the octet is expanded (covalent)
Elements in group 5-7 from period three onwards
Down the periodic table more outer shell electrons are able to take part in bonding
Results in more than 8 in the outer shell
Rules for expansion of the octet
Group 5
- can form 3 or 5(expansion) covalent bonds
Group 6
- can form 2, 4(expansion) or 6(expansion) covalent bonds
Group 7
- can form 1, 3(expansion), 5(expansion) or 7(expansion) covalent bonds
Elements that can expand their octet
Group 5
P, As
Group 6
S
Se
Te
Group 7
Cl
Br
I
At
The larger the bond enthalpy the …
Stronger the covalent bond
