Which of the following is an element?
H2O
Hydrogen
Carbon dioxide
A supernova
Hydrogen.
To determine which of the following is an element, we need to understand what an element is. An element is a pure substance that consists of only one type of atom. It cannot be broken down into simpler substances through chemical means.
Now let's examine the options provided:
1. H2O:
H2O is the chemical formula for water, which is a compound. It consists of two hydrogen atoms bonded to one oxygen atom. Since it is made up of different types of atoms (hydrogen and oxygen), H2O is not an element.
2. Hydrogen:
Hydrogen is the simplest and most abundant element in the universe. It consists of a single atom of hydrogen (H). Therefore, hydrogen is indeed an element.
3. Carbon dioxide:
Carbon dioxide is a compound composed of one carbon atom and two oxygen atoms. As it contains different types of atoms (carbon and oxygen), carbon dioxide is not an element.
4. A supernova:
A supernova is not a substance or a chemical compound; it is an astronomical event that occurs during the death of a massive star. It involves a violent explosion and the release of enormous amounts of energy. Therefore, a supernova is not an element.
In summary, among the given options, "Hydrogen" is the only one that represents an element.