History[ edit ] The composition of coordination complexes have been known since the early s, such as Prussian blue and copper vitriol. The key breakthrough occurred when Alfred Werner reconciled formulas and isomers. He showed, among other things, that the formulas of many cobalt III and chromium III compounds can be understood if the metal has six ligands in an octahedral geometry.
A covalent bond is a shared pair of electrons. The bond between the two atoms of any diatomic gas, such as chlorine gas, Cl2, is certainly equally shared. The two chlorine atoms have exactly the same pull on the pair of electrons, so the bond must be exactly equally shared.
In cesium fluoride the cesium atom certainly donates an electron and the fluoride atom certainly craves an electron. The amount of pull on an atom has on a shared pair of electrons, called electronegativity, is what determines the type of bond between atoms. Considering the Periodic Table without the inert gases, electronegativity is greatest in the upper right of the Periodic Table and lowest at the bottom left.
The bond in francium fluoride should be the most ionic. Some texts refer to a bond that is between covalent and ionic called a polar covalent bond. There is a range of bond between purely ionic and purely covalent that depends upon the electronegativity of the atoms around that bond.
If there is a large difference in electronegativity, the bond has more ionic character. If the electronegativity of the atoms is more similar, the bond has more covalent character. Lewis Structures Lewis structures are an opportunity to better visualize the valence electrons of elements.
In the Lewis model, an element symbol is inside the valence electrons of the s and p practice writing and naming covalent compounds of the outer ring. It is not very convenient to show the Lewis structures of the Transition Elements, the Lanthanides, or Actinides.
The inert gases are shown having the element symbol inside four groups of two electrons symbolized as dots. Two dots are above the symbol, two below, two on the right, and two on the left.
The inert gases have a full shell of valence electrons, so all eight valence electrons appear. Halogens have one of the dots missing. It does not matter on which side of the symbol the dot is missing. Group 1 elements and hydrogen are shown with a single electron in the outer shell.
Group 2 elements are shown with two electrons in the outer shell, but those electrons are not on the same side. Group 3 elements have three dots representing electrons, but the electrons are spread around to one per position, as in Group 2 elements.
Group 4 elements, carbon, silicon, etc. Group 5 elements, nitrogen, phosphorus, etc. In only one position are there two electrons. So Group 5 elements such as nitrogen can either accept three electrons to become a triple negative ion or join in a covalent bond with three other items.
When all three of the unpaired electrons are involved with a covalent bond, there is yet another pair of electrons in the outside shell of Group 5 elements.
Group 6 elements, oxygen, sulfur, etc. Group 7 elements have all of the eight outside electrons spaces filled except for one. The Lewis structure of a Group 7 element will have two dots in all four places around the element symbol except for one. Let's start with two atoms of the same type sharing a pair of electrons.
Chlorine atoms have seven electrons each and would be a lot more stable with eight electrons in the outer shell.
Single chlorine atoms just do not exist because they get together in pairs to share a pair of electrons. The shared pair of electrons make a bond between the atoms. In Lewis structures, the outside electrons are shown with dots and covalent bonds are shown by bars.
This covalent bond between chlorine is one of the most covalent bonds known. A covalent bond is the sharing of a pair of electrons.
The two atoms on either side of the bond are exactly the same, so the amount of "pull" of each atom on the electrons is the same, and the electrons are shared equally. Next, let's consider a molecule in which the atoms bonded are not the same, but the bonds are balanced.
Methane, CH4, is such a molecule. If there were just a carbon and a single hydrogen, the bond between them would not be perfectly covalent. Hydrogen has a slightly lower electronegativity than carbon, so the electrons in a single H-C bond would, on average, be closer to the carbon than the hydrogen.Atomic Structure (AQA GCE AS level chemistry).
Atomic structure, sub-atomic particles, Bohr model and isotopes. Mass spectrometry - introduction (including determination of relative atomic mass, molecular mass).
Electronic Structure of atoms and ionisation energies (7 sections on 3 linked pages) eg. Introduction to s p d f orbitals and electronic energy levels and order of filling of.
CHEMISTRY Naming Compounds Handout page 1 of 12 IONIC COMPOUNDS versus MOLECULAR COMPOUNDS ionic compound: consist of cations shared electrons (covalent bonding) WRITING CHEMICAL FORMULAS GIVEN THE COMPOUND NAME. Honors Chemistry is designed for students who have demonstrated strong ability in previous science courses.
In this fast-paced, demanding course, the main topics--which include atomic theory, nuclear chemistry, periodicity, chemical reactions, stoichiometry, gases, solutions, reaction kinetics, equilibrium, acid-base theory, oxidation-reduction, and organic chemistry--are studied at an.
Chapter 6 Ionic and Covalent Compound Naming (Practice Quiz) (with oxidation numbers and correct subscript latex codes) Take and pass with 70% for 5 point bonus on your test. Activities. A worksheet on writing formulas for ionic compounds.; A fun and exciting activity for naming chemical compounds.; Naming compounds is one of the hardest things for students to learn.
Nov 11, · Describes how to write names and formulas for ionic compounds and covalent compounds. You can see a listing of all my videos at my website, kaja-net.com