1, calcium:
Calcium is a metal element with atomic number 20 and symbol Ca, which is located in the fourth period and IIA group of the periodic table. Calcium is a silvery white solid at room temperature and has active chemical properties, so it exists in the form of ions or compounds in nature.
2. Iron:
Iron is a metallic element with atomic number 26. The chemical formula of iron is Fe, and the English name is Iron. The average relative atomic mass is 55.845. Pure iron is white or silvery white with metallic luster.
3. Aluminum:
Aluminum is a metallic element with the symbol Al, which is a silvery white light metal. It has plasticity. Commodities are often made into bars, sheets, foils, powders, tapes and wires. An oxide film can be formed in humid air to prevent metal corrosion.
4. Silicon:
Silicon is a chemical element, and its chemical symbol is Si, formerly known as silicon. The atomic number is 14 and the relative atomic mass is 28.0855. There are two kinds of allotropes, amorphous silicon and crystalline silicon, which belong to the metal elements of group IVA in the third period of the periodic table of elements.
5. Oxygen:
Oxygen, element symbol O, is located in the group ⅵ a in the second period of the periodic table of elements. 1774, the British scientist Joseph priestley focused the sunlight on the mercury oxide with a lens, and found a gas that could strongly help combustion.