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.
Preschool (US and UK) for ages 2â5. Nursery School (UK and US) for ages 2â5; may also be used to define services for children younger than kindergarten age, especially in countries where kindergarten is compulsory. Grade 0â2, which is also sometimes classified as a daycare service or a crÃ¨che.