Because it has the same kind of atoms through and through. Calcium doesn't contain anything else than calcium. And anything that consists of only one kind of atoms is an element.
the amount of protons in it
its number of protons
They are both elements, form molecules, and will bond with many other elements.
Its numbers of protrons
Both sodium and calcium can occur with a variety of other metallic elements or silicon. Perhaps you would like to review the wikipedia article about feldspar.
Carbon Dioxide (CO2). Compounds tend to be made from 2 or more different elements bonded together either covalently or ionically. They are all made of 2 or more elements bonded together whether those elements are the same or not. The other options are elements (Fe, O, and Ca respectively). They are not bonded to anything and therefore do not make a compound.
its number of protons
its number of protons
Its made from different elements
Calcium itself an element.So there is other elements in calcium.
Calcium is itself an element. Elements do not contain other substances.
They are both elements, form molecules, and will bond with many other elements.
Yes it does react strongly when bonding with other elements
Milk is a complex mixture consisting of water, proteins, fats, lactose (sugar), vitamins, and minerals such as calcium, phosphorus, and potassium. It is not accurate to say that milk is solely made of hydrogen, oxygen, and calcium.
Inert gasses do not react with other elements or compounds.
It combines with Oxygen the most.
The main elements found in teeth are calcium, phosphorus, and trace amounts of other minerals such as fluoride, potassium, and sodium.
Egg yolk contains calcium, iron, magnesium, phosphorus, potassium, zinc and many other elements. Eggs are a good source of may different vitamins and amino acids.