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

Buffers and Equilibriums

Buffers and Equilibriums As shortly explained in the section about how to calculate pH in a solution of dissolved NaHCO3, a buffer has the capability of keeping pH withina certain and narrow range even if an excess of hydrogen ions H+ or hydroxide ions OH- are added. In this particular page I will elaborate a bit on why buffers actually have the ca...

Questions & Answers

Questions & Answers Question about acetate buffer and what happens when HCl is added to such a solutionDebra ask:How do I attack this problem?I want to compare the effect of adding 1mmol of HCL to 100 ml of 0.2M acetate buffer at two different starting pH's. (pKa of acetate buffer =4.7Initial pH = 4.7Initial pH = 5.7Thank youHi Debra,There is bo...

Buffers

Buffers BackgroundAs shortly explained in the section about how to calculate pH in a solution of dissolved NaHCO3 abuffer has the capability of keeping pH within a certain and narrow range even if an excessof hydrogen ions H+ or hydroxide ions OH- are added.In this particular page I will elaborate a bit on why buffers actually have the capabilities ...

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 ...