In this case, the H- has taken the electron pair. However, it is possible that both atoms retain one electron each in a process called 'homolytic cleavage'. These are called 'Free Radicals. These highly reactive molecules will then react quickly with another nearby molecule. Due to how reactive they are, free radicals can be very dangerous.
Free radicals occuring in the human body can attack and damage cells.
This is one reason why fruit and vegetables are so good for us is that they contain anti-oxidants which react with free radicals and stop them harming us. However, free radicals are also very useful in some reactions. For example one method of polymerisation, the process by which plastics are made, depends on free radicals reacting with other molecules, producing more free radicals and making long chain polymers. To summarise, free radicals are highly reactive short lived molecules that have one or more unpaired electrons. Include the above question in your e-mail.