structure and bonding

Ionic Bonding

The electrostatic attraction between oppositely charged ions.

Giant Ionic Lattice

A continuous structure in three dimensions formed of cations and anions arranged in a regular pattern.

Electrostatic Attractions

Strong attractions between positive and negative ions present in ionic compounds.

Delocalised Electrons

Electrons that are free to move throughout a metallic structure, allowing metals to conduct electricity.

Simple Molecular Structure (simple covalent)

A 3D structure held together by weak intermolecular forces, often resulting in low melting points.

Giant Covalent Lattice

A structure where atoms are bonded together by numerous strong covalent bonds in a repeating pattern.

Electrical Conductivity

The ability of a material to conduct electricity, which depends on the presence of mobile charge carriers

Bond Strength

Refers to the strength of the attractions between particles in different types of structures, affecting melting and conductivity.

Conductivity of Ionic Compounds

can conduct electricity when molten or in solution due to the mobility of ions.

Properties of Metals

high melting points

good electrical conductivity due to strong metallic bonding and delocalised electrons.

Weak Intermolecular Forces

Forces that hold simple molecular structures together, generally resulting in lower melting points than ionic or covalent compounds.

Mobile Charge Carriers

Charged entities, such as ions in ionic compounds or delocalised electrons in metals, that enable conductivity.

Acid

A substance that donates protons (H+) in a chemical reaction.

Base

A substance that accepts protons (H+) in a chemical reaction or produces hydroxide ions (OH-).

Salt

An ionic compound formed from the neutralization reaction of an acid and a base.

Metallic Bonding

A type of chemical bonding that occurs in metals, characterized by a sea of delocalized electrons.

Dative Covalent Bond

A bond in which both shared electrons come from the same atom, also known as a coordinate bond.

Lone Pair

A pair of valence electrons that are not involved in bonding.

Bonding Pair

A pair of electrons that are shared between two atoms in a covalent bond.

what are the names of the regular shapes of structures and the num of bonding pairs each has ?

linear - 2 bp 

trigonal planar - 3 bp 

tetrahedral - 4 bp 

octahedral - 6 bp  

what does VSEPR tell us ?

eps in the valence shell repel each other as far apart as possible 

lps repel more than bps 

explain the shape of BeCl2

Be has 2 bps and no lps of electrons in its valence shell 

eps repel each other as far apart as possible

the bond angle around Be is 180 

linear shape 

explain the shape of BF3

B has 3 bps and 0 lps of electrons in its valence shell

eps repel each other as far apart as possible

the bond angle around B is 120 

trigonal planar shape 

explain the shape of CH4

C has 4 bps and 0 lps of electrons in its valence shell

eps repel each other as far apart as possible 

bond angle around C is 109.5 

tetrahedral shape

explain the shape of SF6

S has 6 bps and o lps of electrons in its valence shell 

eps repel each other as far apart as possible 

bond angle around S is 90 

octahedral shape 

explain the shape of NH3

N has 3 bps and 1 lp of electrons in its valence shell 

eps repel each other as far apart as possible but lps repel 2.5 more than bps

bond angle around N is 107 - 2.5 less than tetrahedral

pyramidal shape

explain the shape of of H2O

O has 2 bps and 2 lps of electrons in its valence shell 

eps repel each other as far apart as possible but lps repel more 

bond angle around O is 104.5 - 5 less than a tetrahedral

non linear shape

when trying to work out the shape of a molecule what do u do w/ double or triple bonds ?

count them as a single bonding region

electronegativity 

the ability of an atom to attract bps of electrons in a covalent bond 

incs as u go up and across the table 

in electronegativity which bond is the only exception ?

the C-H bond which is considered non polar 

how is electronegativity measured ?

the pauling scale

if the difference between the electronegativity values is : 

0 = non polar covalent 

between 0 and or equal to 1.8 = polar covalent 

>1.8= ionic 

what are the factors affecting electronegativity ?

nuclear charge 

atomic radius 

shielding 

atomic attraction 

trend across a period in electronegativity ?

electronegativity incs

nuclear charge incs 

atomic radius decs 

so stronger attraction between nucleus and bp of electrons 

is H2O a polar or no polar molecule and why ?

it has an asymmetrical structure bcs one area has more es than another

it has polar bonds

polar molecule therefore dipoles do not cancel out 

is SiH4 a polar or non polar molecule and why ?

its electrons directions are not around the central atom so its symmetrical

has polar bonds but the the dipoles cancel out so its a non polar molecule 

having an asymmetrical structure makes a molecule ?

polar

having a symmetrical structure makes a molecule ?

non polar 

to be polar a molecule must ….

have polar bonds and be asymmetrical

structure of diamond ?

giant covalent lattice

each c atom bonded to 4 others

high mp

tetrahedral shape

rigid and hard

not conductor

strong covalent bonds

graphite structure

giant covalent lattice

strong covalnt bonds within layers but weak ldn forces between layers

each c atom bonded to 3 others

lubricant 

conductor

graphene

single 2d sheets of graphite

one atom thick

hexagonal c rings form lightweight materials

conductor

what are D block elements ?

elements w/ valence electrons in the d subshell

what are transition elements ?

elements forming one or more ions w/ incomplete d subshells

are all d block elements transition metals?

no bcs Sc and Zn form ions with empty or complete d subshells e.g. Sc3+ or Zn2+