4. Bonding Flashcards
(28 cards)
The 3 types of bonding are…
Ionic, Metallic, Covalent
Ionic bonding happens by…
A transfer of electrons from a metal to a non-metal to form a 3D lattice
An ionic bond is…
the electrostatic attraction between oppositely charged ions
In forming an ionic bond the metal…
Looses electrons (is oxidised) to become a positive cation
In forming an ionic bond the non-metal…
Gains electrons (is reduced) to become a negative anion
The melting point of ionic compounds is..
high because of the strong electrostatic attraction between oppositely charged ions
MgO has a higher melting point than NaCl because…
2 electrons are transferred in MgO compared to 1 in NaCl therefore there is a stronger electrostatic attraction between oppositely charged ions
Ionic compounds and conduction…
Don’t conduct when solid because the ions aren’t free to move. Do conduct when molten or dissolved because the ions are free to move.
Covalent bonding happens by…
Two or more non-metals sharing a pair of electrons
A covalent bond is…
A shared pair of electrons held in place by the attraction between the electrons and the nuclei of the atoms either side
A stick diagram for HCl looks like…
H-Cl
A stick diagram for H2 looks like…
H-H
A stick diagram for H2O looks like…
H-O-H
A stick diagram for O2 looks like…
O=O
A stick diagram for CO2 looks like…
O=C=O
The pros and cons of a stick diagram are…
Pro: Shows all the bonds and the type (single, double etc)
Con: Doesn’t show 3D shape or correct bond angles
The pros and cons of a dot and cross diagram are…
Pro: shows which atoms the electrons in the bond come from
Con: Doesn’t show relative size or shape of molecule
A metallic structure can be described as…
Layers of positively charged cations surrounded by a sea of ‘delocalised’ electrons
Metals are held together by…
strong electrostatic forces of attraction between cations and the delocalised electrons
Metals can conduct because…
The delocalised electrons are free to move
Metals are malleable because…
The layers of ions can slide over each other without breaking the attraction to the delocalised electrons
Metals have high melting points because…
There are strong electrostatic forces of attraction between cations and the delocalised electrons
A molecule is…
Two or more atoms joined together in an individual unit with a set number of atoms
A lattice is…
A regular array of atoms or ions with no set number
