Chemistry: Structure and Bonding (Polarity (The polarity is shown by…
Chemistry: Structure and Bonding
The electron density maps shows you were the electrons are and can tell you what kind of bond is present in a compound/ element
Polarity is a separation of electric charge leading to a molecule having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms.
The polarity is shown by these values:
Nonpolar Covalent: 0-0.4
Polar Covalent: 0.5-1.9
We can see if ions exist by rubbing a rod or a ruler on a cloth and then putting it against a stream of water which will cause it to bend if ions do exist
Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms. A nonpolar covalent bond is when the electrons are shared equally towards the middle instead of being closer to one side. Ionic bonds is when electrons are given away to another meaning heres no interlinking bonds apart from the attraction between them. Dative covalent bonds or a coordinate covalent bond is a when a pair of electrons are shared which come from the same atom
Giant Ionic and Covalent Structures
An example of a giant covalent structure would be Graphite, Diamond or Silicon Dioxide
Substances with giant covalent structures have very high boiling and melting points, because a lot of strong covalent bonds must be broken.
Giant covalent structures contain a lot of non-metal atoms, each joined to adjacent atoms by covalent bonds. The atoms are usually arranged into giant regular lattices, this means they are extremely strong structures because of the many bonds involved
A ionic compound is a compound made up of oppositely charged ions bonded to each other in a giant lattice. Ionic compound form giant three-dimensional networks called lattices
This is the structure of NaCl
When it is a liquid form, the ions are free to move around so it can conduct electricity. When it is in a solid state, the ions are fixed in place so the ions cannot move around so it cannot conduct electricity.
Metallic Bonding and Giant Metallic Structure
A metallic bond is a type of chemical bond formed between positively charged atoms in which the free electrons are shared among a lattice of cations.
The structure of Magnesium
Metals are malleable because of the ability of the atoms to roll over each other into new positions without breaking the metallic bond, which is also due to the ions being arranged in layers
Due to the atoms becoming ions in the metallic structure then an electron is expelled and in the structure it forms a sea of delocalised electrons which can travel freely and in one direction when current is applied
Shapes of Molecules and IMFs
Hydrogen bonds are formed between familiar molecules and dipole-dipole but the other one are formed between unfamiliar ones
Valence shell electron pair repulsion (VSEPR) theory is a model used to predict the shape of individual molecules from the number of electron pairs surrounding their central atom etc.
Melting and boiling points change due to the type of bonding present in them. These types include Ionic, Hydrogen bonding, van der waals dipole-dipole and london dispersion forces as well
Dot and Cross Diagrams Representing Ionic and Covalent Bonds
This is the dot and cross of CO2
Ionic bonds form between a non-metal and a metal atoms in which they donate electrons to reach the most stable it can be (Full outer shells)
Oxygen has a double covalent bond between each other in order to fully complete their outer shell w electrons (8 electrons in the outer is a full one other than the first shell)
The charge on an Aluminium ion would be 3+ and a Nitride has the charge of 3-
Covalent bonds are formed when two non-metal atoms come together and share electrons
This is the dot and cross of Na2S
Simple Molecular Structure
Mostly all simple molecular structures gases or liquids at room temperature due to there being weak bonds between each pairing of molecules holding them together but the bonds between each pair are strong
A molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
A simple molecular structure is a structure made up of individual molecules