Note that there are now several types of treatments and medical providers for which Medicare Part B pays 100% of the approved charges rather than the usual 80%. These categories of care include home health care, clinical laboratory services, and flu and pneumonia vaccines.
A giant covalent structure is a three dimensional structure of atoms held together (obviously) by Covalent bonds. These atoms are often all the same-so the elements Silicon and Carbon in the allotropes Diamond and Graphite are Giant Covalent structures.
NH3 is definitely covalent. Hydrogen is an element that is sometimes placed on both the left side and the right side of the periodic table. One of the deficiencies of the rectangular table is that hydrogen doesn't really belong to a specific spot. Some other shapes and designs try to rectify this flaw. simple way to decide if a substance is covalent or ionic is to compare the electronegativities of the elements involved in the bonding. Electronegativity is a measure of the pull on shared electrons between to atoms.