Ions and compounds

Atoms are made up of neutrons that are neutral and have no charge, protons with a positive charge andelectrons with a negative charge.

An ion is an entity or a group of atoms with a positive or negative charge such as the positively charged hydrogen ion H+ and thenegatively charged nitrate ion NO3-. Negatively charged ions are also called anions while positively charged ions are called cations.

A compound is something that is made up oftwo or more simple substances. Ammonia NH3 is a compound without a charge.

Atom model

Below it is shown how positively charged protons (yellow) and neutral neutrons constitutes a nucleusin the atom while the negatively charges electrons orbits the nucleus. This is a very simple model of the atom.A more complicated model would include a nucleus surrounded by orbitals with electrons in them orbiting the nucleus.


Web resources

A philosophical approach to atoms
A full course about atoms and ions
Encarta - encyclopedia

Ions and compounds

Acids and bases - Broensted-Lowry definition

Acids and bases - Broensted-Lowry definition A more fundamental definition of acids and bases than the one provided on the index page was given by the Danish chemists Johannes Broensted. The definitions are:A Broensted acid is a proton doner.A Broensted base is a proton acceptor. The English chemist, Thomas Lowry, proposed exactly the same at roug...

NaHCO3 dissolved in water - how is pH calculated?

NaHCO3 dissolved in water - how is pH calculated? Background about buffersA buffer is a solution that has the ability to keep pH within a certain and narrow range: even if an excessof hydrogen ions (H+) is applied to the solution. In other words:buffers resist changes in pH whenreasonable amount of either H+ or OH- is added to the buffer solution.Th...

pH strips

pH strips Background Substances with the property to change color when they come into contact with an either acidic or basicsolution are called pH indicators. This is used in pH strips that changes color when they come into contactwith hydrogen ions (H+) and hydroxide ions (OH-). Usually, pH strips are b...

Question about acetate buffer

Question about acetate buffer This is the long and computational answer to Debra's question about what happens when 100 mmol of HCl ispoured into an 100 ml acetate buffer (0.2 M) 06.07.2019 Author: Jim ...