Period 1 element lithium and fluorine (appearing twice), or left floating above the other elements and not assigned to any group in the periodic table. Helium is almost always placed above neon (which is in the p-block) in the periodic table as a noble gas, although it is occasionally placed above beryllium due to their similar electron configuration. Hydrogen (H) is the chemical element with atomic number 1. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H. With an atomic mass of 1.00794 amu, hydrogen is the lightest element. Hydrogen is
Canonical link element document. 11. Site Host https://sitehostnp.com/canonicalization/canonical-link-element/. What s "rel=canonical" link element and how it should be used for search engines. Published on 14 June 2018. Canonical link element A canonical link element is an HTML element that helps webmasters prevent duplicate content issues in search engine optimization by specifying the "canonical" or "preferred" version of a web page. It is described in RFC 6596, which went live in April 2012. A major problem for search engines is to determine the original source for documents that are available on multiple URLs. Content duplication can happen in a many ways, including: Duplicate content