Questions 1-20 are statements. Common table salt is composed of sodium cations and chloride anions. Fluorine is an element in the alkali metal group of the Periodic Table. In a pure element or compound the number of protons is equal to the number of electrons. Isotopes are atoms of an element that have a different number of neutrons in the nucleus.
Sulfur is a silvery metal which is a good conductor of electricity.
Elements with the same number of valence electrons have similar chemical properties and generally form ions with the same charge. There are more transition metals than non-metallic elements in the Periodic Table. An element in the third row of the Periodic Table has electrons in f orbitals. In 10.0g samples of water and hydrogen peroxide, there are equal numbers of molecules, and so equal numbers of hydrogen atoms. When 10.08 g of hydrogen is burned, 170.19 g of water is formed.