Methane is a gas made up of 1 carbon atom for every 4 hydrogen atoms. The central carbon atom forms covalent bonds with these 4 hydrogen atoms (they share an electron each), and this sharing completes the outer shell of both the carbon atom and the hydrogens (making these atoms stable and happy). The 4 hydrogens around the central carbon means there are 4 groups of electrons around this carbon, creating a tetrahedral shape of the molecule. Tetrahedral shaped molecules form bond angles of 109 degrees.