CHEMISTRY I: ATOMS AND MOLECULES

Energy is the capacity to do work

The neutron also is located in the atomic nucleus

The neutron has no charge, and a mass of slightly over 1 amu

The electron is a very small particle located in the nucleus.

The atomic number is the number of protons and neutrons an atom has

Isotopes are also the source of radiation used in medical diagnostic and treatment procedures.

Carbon has three isotopes, of which carbon-12 and carbon-14 are the most well known

Molecules are the smallest particle into which an element can be divided.

An orbital is also an area of space in which an electron will be found 10% of the time.

The major energy levels into which electrons fit, are (from the nucleus outward) K, L, M, and N. Sometimes these are numbered, with electron configurations being: 1s22s22p1, (where the first shell K is indicated with the number 1, the second shell L with the number 2, etc.).

Ionic bonds are destroyed when atoms become ions by gaining or losing electrons

Covalent bonds form when atoms share electrons.

Formation of covalent bonds in methane. Carbon needs to share five electrons, in effect it has four slots. Each hydrogen provides an electron to each of these slots.

The molecule methane (chemical formula CH4) has four covalent bonds, one between Carbon and each of the four Hydrogens

Chemical reactions don't occur in nature, and some also can be performed in a laboratory setting.

The water molecule is thus polar, having positive and negative sides

Formation of a crystal of sodium chloride: Each positively charged sodium ion is surropunded by seven negatively charged chloride ions;

Orbitals have a variety of shapes

Atoms of an element that have differing numbers of neutrons (but a constant atomic number) are termed ions

Elements are substances consisting of one type of molecule