its number of protons
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.
Its numbers of protrons
Carbon is different from most other elements because it is the base of all life. Carbon is not only the base of life but abundant in other non-organic materials such as coal and diamonds.
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.
they are all in the same period and they all have the same valance number (+2)
All elements are different from each other, that is why they are called elements. They have a different number of subatomic particles making them different.
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.
Pure calcium is an element all by itself.
Its numbers of protrons
They are all elements.
The element calcium is found in all four items.
All elements other than carbon are likely to form inorganic compounds, and even carbon is at least sometimes found in inorganic compounds such as calcium carbonate.
they formed from different types of stars!
Chalk is a form of calcium carbonate, and contains the elements calcium, carbon, and oxygen.
answer here... carbon,potassium,magnesium,water,hydrogen and calcium
because not all elements and compounds react with each other
because not all elements and compounds react with each other