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.
River Liffey. The River Liffey rises in the Wicklow Mountains 12 miles south of the city of Dublin. From its source it flows in a long crescent for over 80 miles before entering the sea at Dublin Bay.The riverâs upper reaches from Sally Gap to Pollaphuca.Reservoir hold good stocks of very small trout.iver Liffey. The River Liffey rises in the Wicklow Mountains 12 miles south of the city of Dublin. From its source it flows in a long crescent for over 80 miles before entering the sea at Dublin Bay. The riverâs upper reaches from Sally Gap to Pollaphuca. Reservoir hold good stocks of very small trout.