The atoms form a double bond because there is a strong enough attraction in both directions and room for the electrons in the outer energy level of the atoms. The carbon atom and hydrogen atoms are ...

Now, to make the diagrams simpler we often just draw ... chemical bond between atoms is shown as a stick. One molecule of the compound methane is made from one carbon atom and four hydrogen ...

Now, to make the diagrams simpler we often just draw ... chemical bond between atoms is shown as a stick. One molecule of the compound methane is made from one carbon atom and four hydrogen ...

In these drawings, every line is a bond and every bend is a carbon atom. Most hydrogen atoms are not shown, and it is assumed each carbon has enough hydrogens so that each carbon has four bonds.