Pulmonary arterial hypertension is a rare but severe disease with an estimated five-year survival rate of only 57% after diagnosis, according to the Registry to Evaluate Early And Long-term PAH disease management (REVEAL), which registers data from patients in the United States.
Concentration of elements in the ocean relative to the total concentration in the bulk silicate Earth (BSE). Of all the elements, only Cl and Br have a significant fraction in the ocean (see inset), indicating the extreme hydrophilic character for the heavier halogens.
Chlorine is the second element in the seventeenth column of the periodic table. It is classified as a member of the halogen group. It has 17 electrons and 17 protons with 7 valence electrons in the outer shell. It is about the twentieth most abundant element in the Earth's crust. Characteristics and Properties. Under standard conditions chlorine is a gas that forms diatomic molecules.