Elements are more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e., the number of protons in the nuclei of its atom, also known as the basic unit of a chemical element. Protons are subatomic particles, which are particles smaller than an atom. Electrons, and neutrons are also examples of subatomic particles but they all have different charges. A proton has a positive charge, an electron has a negative charge, and a neutron has no charge. Molecules, also known as groups of atoms bonded together, form chemical compounds that take part in a chemical reaction. Molecules use bonds to form into compounds. An ionic bond is a chemical bond in which the atom transfers electrons while a covalent bond is a chemical bond in which the atoms share electrons. A chemical formula is a way of expressing the information about what makes up the compound. Two examples of compounds are organic compounds, and inorganic compounds. Organic compounds are made up of the elements carbon and hydrogen, while inorganic compounds have either of the elements, hydrogen and carbon. Macromolecules also known as “big molecules,” are made from thousands or even hundreds of thousands of even smaller molecules. Four examples of macromolecules are proteins, carbohydrates, lipids, and nucleic acids. Carbohydrates are made up of monosaccharides, simple sugar molecules that
CHEM 251 EXAM 1 REVIEW
Chapter 1 – 60 points
Definition of organic compounds-two main elements-why carbon is so important
Organic compounds or organic molecule is a chemical which mainly contains carbon, forming carbon-carbon bonds and carbon-hydrogen.
Carbon is the key for:
-Diversity of compounds possible thanks to forms chaims easily
-Forms 4 covalent bounds, especially other carbom atoms and can form chains of carbom atoms with very strong bonds.
This layer of silica surface has atoms attached to hydroxyl group and the surface is very polar.
Different compounds in the mixture travel at different rates due to the difference in the attraction to the stationary phase and the differences in solubility…
CHEM 220B: Organic Chemisty
Formerly used to describe fragrant substances
Now used to refer to the class of compounds that contain
six-membered benzene-like rings with three double bonds
(1) the number of neutrons in the atom
(2) the number of protons in the atom
(3) the number of valence electrons in the atom
(4) the total number of electrons in the atom
5 The region that is the most probable location of
an electron in an atom is
(1) the nucleus…
A common property of coordination compounds is that they often occur in isomeric forms having the same empirical
formula, but with a different arrangement of atoms. Many types of isomerism exist, more so than in organic chemistry
e.g. geometrical, optical, ionisation, ligand isomerism etc. (see CH160 lecture notes). Linkage isomers arise because
some ligands can bond via one donor atom in one compound, but via a different atom of the same ligand in another
incompletely filled in outer shell
Able to react with other atoms to form molecules
Chemical bonds to stabilize electrons
Ionic – electrons are donated by one atom to another
Covalent – electrons share a pair of electrons
The number of electrons an atom must acquire or lose to fill outer shell determines the number of bonds an atom can make.…
Some properties such as reactivity relate to the elements electron configuration (Chem Wiki, 2014).
Reactivity is the exchange of electrons that leads to the formation of compounds and molecules. It refers to the difficulty at which elements react with each other. When an element has a high reactivity it means that it reacts fast with different particles because it has an almost full or almost empty valence shell, for an example, group 1 or 7.…
These techniques were introduced in CHEM 2020, with the exception of column chromatography which will be learned in this lab.
Chromatography is a very common technique used often in synthetic chemistry labs and is also used for instrumental analyses of organic compounds to establish purity.…