Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetallic element and oxidizing agent that readily forms compounds (notably oxides) with most elements. Photosynthesis releases oxygen, and respiration consumes oxygen.xygen constitutes 49.2% of the Earth's crust by mass and is the major component of the world's oceans (88.8% by mass). Oxygen gas is the second most common component of the Earth's atmosphere, taking up 20.8% of its volume and 23.1% of its mass (some 10 15 tonnes).
The River Liffey (Irish: An Life) is a river in Ireland, which flows through the centre of Dublin.
Most visitors to this fair Irish city will pass through Dublin Airport, one of the busiest airports in Europe and portal to many major cities around the world. Sitting at a mere thirty minutes from the city centre, Dublinâs airport can be a handy hotel spot for business travelers and city break visitors on short trips. It is situated on the east of Ireland and is surrounded by Dublinâs stunning countryside, picturesque coastline and greater Dublin area.