periodicity- chapter 7 Flashcards
what is ionisation energy
measures how easily and atom loses electrons to form positive ions
what is the first ionisation energy
the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1= ions
how does the atomic radius affect ionisation energy
the greater the distance between the nucleus and the outer electrons, the less nuclear attraction
the force of the attraction falls off sharply with increasing distance, so atomic radius has a large effect
how does nuclear charge affect ionisation energy
the more protons there are in the nucleus of an atom, the greater the attraction between the nucleus and the outer electrons
how does electron shielding affect the ionisation energy
electrons are negatively charged and so inner-shell electrons repel outer-shell electrons
this repulsion called the shielding effect, reduces the attraction between the nucleus and the outer electrons
how are successive ionisation energies defined as
same as the first ionisation energy
define second ionisation energy
energy reunite to remove one electron from each ion in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions
what are 3 predictions that ionisation energies show
- the number of electrons in the outer shell
- the group of the element is in the periodic table
- the identity of an element
describe the structure bonding in metals (when in a solid metal structure)
- in a solid metal structure, each atom has donated is negative outer shell electrons to a shared pool of electron, which are delocalised throughout the whole structure
- the positive ions left behind consist of the nucleus and inner electrons shells of the metal atoms
what is metallic bonding (describe the 2 parts to metallic bonding)
the strong electrostatic attraction between cations and delocalised electrons
-cations are in a fixed position, maintaining the structure and shape of the metal
-the delocalised electrons are mobile and able to move throughout the structure, only electrons move
what structure does metal structure form
giant metallic lattice
what are 3 properties of metal
- strong metallic bonds
- high electrical conductivity
- high melting and boiling points
describe electrical conductivity in metals
-conduct electricity in solid and liquid states
-when a voltage is applied across a metal, the delocalised electrons can move through the structure, carrying a charge
explain melting and boiling points in metals
- most have high melting and boiling points
- melting points depend on the strength of the metallic bonds holding together the atoms in the giant metallic lattice
- for most, high temperature are necessary to provide the large amount of energy needed to overcome the strong electrostatic attraction between the cations and electrons
what is the bond angle in carbon (diamond) and the structure
109.5
tetrahedral
describe the melting and boiling points in giant covalent lattices
HIGH melting and boiling points due to strong covalent bonds, high temperature are necessary to provide the large quantity of energy needed to break the strong covalent bonds
describe solubility in giant covalent lattices
insoluble in almost all solvent, covalent bonds holding together the atoms in the lattice are too strong to be broken by interaction with solvents
describe the electrical conductivity in giant covalent lattices
NON CONDUCTORS of electricity, exceptions=graphene and graphite
