Unit 1 - Chemical Changes and Structure Flashcards
(45 cards)
Covalent radius
Half the distance
between the nuclei of 2 of its bonded atoms.
What happens to the covalent radius as you go
across a period?
It decreases due to increased atomic number.
What happens to the covalent radius as you go down
a group?
It increases due to increased electron shielding.
Ionization energy
The energy required to remove one mole of electrons
from one mole of atoms in the gaseous state
The strength of metallic bonding _____ as you go along a period.
Increases, due to increased numbers of delocalized electrons.
The strength of
metallic bonding
________ as you
go down a group
Decreases.
Intramolecular forces
The strong attraction between atoms and molecules
Intermolecular forces
The weak attraction in-between different molecules
Three types of Van der Vaals intramolecular forces
- London dispersion forces
- PD-PD
- hydrogen bonding
What molecules create hydrogen bonding?
NH, OH or FH
Electronegativity
Electronegativity is a measure of the attraction an atom involved in a bond has for the electrons in a bond.
Elements at the top________ hand side of the periodic table e.g. F .0, N are the _______electronegative.
Right, most.
Elements at the bottom _______ hand side of the periodic table e.g. K, Rb, Cs are the ______ electronegative.
Left, least.
Electronegativity ________________ as we go along a period.
Increases.
Electronegativity ________________ as we go down a group.
Decreases.
The strength of London dispersion force _______ as the size of the atoms increase.
Increases.
Covalent molecular substances have ______________melting points and boiling points
Low.
Within covalent molecules there are strong _____________ bonds
Intramolecular.
Polymorphs are___
different crystalline forms of the same element
Fullerenes are a large family of ‘carbon cage’ molecules each made up of rings of _____ and _____ carbon atoms.
5&6
C60 is called..
Buckminsterfullerene
With no ‘free’_____________ fullerenes are normally poor conductors
Electrons
Nanotubes are…
fullerenes made from ‘tubes’ of 6-carbon rings rather like a rolled up sheet of graphite
polymorphs of carbon
diamond & graphite
