An element is a substance made from only one type of atom (e.g. oxygen is an element made up of only oxygen atoms).
An atom is the simplest form of an element that can exist, such as a lithium atom (Li).
Atoms of different elements can be combined together to create compounds, e.g sodium oxide (Na2O).
A molecule is a combination of 2 or more atoms that form chemical bonds. When these atoms are of the same element, they can be called molecules (e.g. O3 - ozone).
However when a molecule is made up of atoms of different elements, they are classified as compounds (e.g. CO2 - carbon dioxide).
So all compounds are molecules, but not all molecules are compounds.
The correct option is C.
The density of an object refers to its mass per volume. Water and ice have different densities. The differences in their densities is due to the empty spaces which exist in the structure of ice. Because of the empty spaces, the structure of ice occupy more volume than that of water, hence it is less dense than water.
The process is replication
<span>A metal is one which ionizes easily and gives electrons whencompared to other elements.
So it should have a lower ionization energy.
Hence we would expect element 2 to be a metal.</span>
