Part B. Complete the following sentences using the word bank. Electron lon Neutron Nucleus Proton 1. Every atom contains a _which is positively charge. 2. The nucleus of an atom is composed of and 3. The in an atom move about on the space surrounding the nucleus. 4. A charged atom is called 5. An uncharged atom has an equal number of and

Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. More than 99.94% of an atom's mass is in the nucleus.

The nucleus is the positively charged centre of an atom and contains most of its mass. It is composed of protons, which have a positive charge, and neutrons, which have no charge. Protons, neutrons, and the electrons surrounding them are long-lived particles present in all ordinary, naturally occurring atoms.

Around this nucleus is a cloud of electrons. Electrons move about in random motion at different levels around the nucleus depending on their energy. The greater the energy of the electron the further away from the nucleus the electron can be found.

ion, any atom or group of atoms that bears one or more positive or negative electrical charges. Positively charged ions are called cations; negatively charged ions, anions.

Atoms are made up of three sub-atomic particles; Protons, Neutrons and Electrons. Protons have a positive charge. Electrons have a negative charge. For an atom to be uncharged, the total number of protons and electrons in the atom must be equal.