Answer:
Compound B and D
Explanation:
Both are good conductors of electricity.
Answer:
The chemical elements are arranged in order of increasing atomic number.
Explanation:
Hydrogen = 1
Helium = 2
Lithium = 3
Answer: When a substance is pure, it is composed of one type of molecule. For example, table salt is only composed of (more or less) salt molecules, while seawater has water and salt molecules. A more complicated example of a non - pure substance is soil. It has many different types of nutrients and compounds.
When a radioactive isotope releases an alpha particle, the atomic number of the atom is decreased by four.
So, the correct answer is B.
Hope this helps,
Davinia.
Energy diagram for and endothermic and exothermic reaction
