3 of 50 What are bonds? Compounds are formed when different elements chemically react and form bonds with each other. Some compounds, like water (H 2 0), have small, simple structures with just a few atoms bonded together. Others compounds, like DNA, have large, complex structures containing thousands or even millions of bonded atoms. Elements are the simplest substances that exist on Earth. Each element is made up of just one type of atom, usually joined to other atoms of the same element by bonds. This forms molecules such as chlorine (Cl 2 ).
31 of 50 What is the ratio of ions? Sodium chloride (NaCl) and magnesium oxide (MgO) are simple ionic compounds. Both compounds have a 1:1 ratio of metal ions to non-metal ions, which is shown by the formula of each compound. Na ClNa + Cl - 1 electron Mg Mg 2+ O O 2- 2 electrons In each compound, the metal needs to lose the same number of electrons that the non-metal needs to gain.
40 of 50 What is an ionic lattice? In an ionic compound, millions and millions of ions are packed together in a regular cubic arrangement, joined by ionic bonds. The structure of the ionic lattice affects the properties of the ionic compound. The ionic lattice will continue to build in this way until there are no more ions left to add. This forms a giant 3D structure called an ionic lattice.
48 of 50 Glossary bond – A strong force that joins atoms or ions together in molecules and giant lattices. compound ion – An ion made up of a group of atoms, rather than one single atom. ionic bond – The electrostatic force of attraction between oppositely charged ions. ionic compound – A compound made up of ions. ionic lattice – A giant 3D structure of closely packed, oppositely-charged ions. negative ion – An atom or group of atoms that has gained electrons and so has a negative charge. noble gas – An element that has a full outer electron shell and so is very stable and unreactive. positive ion – An atom or group of atoms that has lost electrons and so has a positive charge.