Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major formsâ white phosphorus and red phosphorus âbut due to its high reactivity, phosphorus is never found as a free element on Earth. Instead phosphorus-containing minerals are almost always present in their maximally oxidised state, as inorganic phosphate rocks.
Ages & Stages â Preschool Children. Three and four-year-old children are often called preschoolers. Preschool children want to touch, taste, smell, hear, and test things for themselves. They are eager to learn. They learn by experiencing and by doing. Preschoolers learn from their play.
This article is about schools for younger children between the ages of three and five or seven, prior to the start of compulsory education. For other, see Preschool (disambiguation). Preschooler redirects here. For The stage of childhood, which ranges from 3 to 5 years old, see Early childhood.